Well-being in romantic relationships: the role of motivation and conflict engagement

Abstract

Relationship science emphasises that most people desire romantic relationships. Self-determination theory provides a theoretical approach that can capture the variety of motivations potentially underlying the pursuit of romantic relationships. Within this framework, couple and sexual motivations can help us to understand why people are in relationships, what motivates them to stay together and what can increase the risk of conflict. Indeed, how couples manage conflict can explain personal and couples’ well-being within close relationships. Grounded in self-determination theory, a Structural Equation Model was tested to investigate the role of couple and sexual motivation by both partners in associating couple and individual well-being by both. We also examined whether conflict engagement played an intervening role in associations of motivation with well-being. 402 heterosexual young adult couples, aged 20 to 30, who had been in a stable relationship for between 1 and 5 years, participated in the study via a snowball recruitment technique. Using the Actor Partner Interdependence Model (APIM), results showed that couple motivation in both partners is positively related to their own couple and individual well-being. Female sexual motivation is positively related to their own individual well-being. An indirect association is found in both partners between couple motivation and individual well-being through the mediation of conflict engagement. In line with SDT, motivation emerges as a critical factor in the promotion of both individual and couple well-being and in the adoption of functional conflict resolution strategies. The theoretical and practical implications of the findings for future research and interventions are discussed.

Introduction

A fundamental assumption in relationship science is that most people desire a romantic relationship [1]. Extensive research has examined why close and romantic relationships are central to human life, consistently showing that satisfying partnerships provide social support, happiness, and well-being. Romantic relationships also fulfil fundamental needs for connection, closeness, intimacy, and emotional support, and therefore represent a key point of reference across the lifespan [2, 3]. Beyond the well-documented consequences of being in a romantic relationship, researchers have also examined the reasons why individuals seek and maintain such partnerships. Evolutionary perspectives suggest that desires for sex, belongingness, and emotional attachment, are universal desires, positioning romantic partnerships as a primary context through which people pursue these innate needs [1, 4].

However, what remains insufficiently understood is how these desire-driven tendencies translate into behaviour and shape partners’ wellbeing. A growing line of research emphasizes the role of self-determination processes in relationships, proposing that the quality of one’s motivation—not only the presence of desire—plays a central role in determining how individuals engage with others. This perspective takes a motivational approach to shedding light on the mechanisms underlying the functioning of relationships, including romantic ones.

The self-determination continuum of motivation

Although the idea that various motivations underpin the pursuit of romantic relationships is widely accepted, identifying the specific motivations remains challenging [1]. In line with previous studies, feelings of sexual connection and significant bonding with others can be integrated, organised and understood within the Self-Determination Theory (SDT) framework [5]. SDT has received significant empirical support when applied to various themes, such as education [6], sports and leisure [7] and parenting [8]. SDT has also been applied to interpersonal relationships, including romantic relationships [9, 10]. SDT is a meta-theory of human motivation which considers the extent to which one’s behaviours originate from within oneself (i.e. are autonomous) versus from intrapersonal or interpersonal pressure (i.e. are controlled). Examining self-determination in romantic relationships is important because the motivational processes affected by self-determination may be key to maintaining relationships [2, 3]. SDT proposes a taxonomy of motivation that organises motives along a continuum. This continuum ranges from being controlled to being fully autonomous. At one end of the continuum there is amotivation: the person who lacks the intention to act, does not act, or acts without intent, as when partners feel there is nothing, they can do to improve their relationship, they haven’t a clue as to why they are in the relationship or they may lack the intention to have sex with their partner. This is followed by external motivation: instrumental motivations emerge to obtain reinforcement or avoid punishment, such as when the individual decides to spend time with their partner just to avoid complaints or to obtain favours such as for money or when people have sex due to their anxiety about losing their partner [10]. Introjected motivation follows: the person acts to increase their self-esteem to avoid the sense of guilt or shame [11]. For example, people may decide to spend time with their respective partner because they feel compelled to do so because society mandates that they be marriedand or they would feel guilty if they do not fill the role of good lover during sex. Identified motivation involves a more choice-based form of regulation such as when partners decide to engage in a close and intimate relationship because part of their identity is to be engaged or because they consider sex important for relational intimacy, even when sexual desire decreases [12]. In addition, there is integrated motivation, in which the person not only identifies with the behaviour enacted but has also a high relevance as it is in compliance with personal values and needs. For example, being in a satisfying romantic relationship or engaging in sexual activities such as an integral and meaningful part of one’s identity. On the opposite end of the continuum there is intrinsic motivation, the prototype of a highly autonomous and self-determined behaviour. Examples include beginning a relationship for the pleasure of being with a partner or enjoying moments of happiness with them or perceiving and enjoying sexual activity as intrinsically fun and interesting; it is the view that sex is fun and interesting [10]. Thus, the motivational continuum starts with amotivation and progresses through the more controlled forms of motivation (extrinsic and introjected) to the ever more autonomous forms (identified, integrated and intrinsic). Since there may be several reasons, any given behaviour is generated by a combination of these regulations reflecting the relative autonomy for engaging in the behaviour [2, 3]. According to SDT, optimal functioning depends on the extent to which a person’s behaviour is self-determined; in other words, driven by as many autonomous motivations.

Couple motivation and sexual motivation

Motivation, as a process that exerts a good influence on behaviour, is represented as an important antecedent in the partner choice, in the quality of romantic relationships, as well as in the development or failure of romantic relationships [1, 3, 4]. In addition to this, when partners perceive their couple behaviours to be responsive to their personal dispositions, they are more likely to experience relationship satisfaction and better personal adjustment [11]. It has been observed that motivational styles impact the quality of interactions [3, 12], and that numerous self-determined motivations preserve the relationship and are associated with more positive, open, and adaptive relationships [2]. For this reason, it is necessary to distinguish the motivations behind different activities that couples engage in, and focus on these motivations within the same study, in order to understand how individuals behave within specific relationships. The approaches to motivation are characterised by a multi-level evaluation, regarding romantic relationships [1, 2, 4]. Individuals may be potentially motivated in different ways towards specific activities in their relationships.

The feeling of being connected and significantly bound to others [13] represents one of the most important motivations. Blais and al. [9] studied couple motivation as they believe that the motivational styles of everyone to engage or maintain the relationship with their respective partner are a crucial variable for understanding the quality of the relationship. Indeed, SDT also emphasises that the connection with others, that is, feeling personally accepted and meaningful for the partner, feeling cared for and taking care of someone, responds to a motivation orientation that guides, engages and maintains involvement in a relationship [3, 5]. Every person is motivated to fulfil this goal and couple motivation is fundamental for human well-being. The results indicate that the more autonomous the motivations to maintain the relationship, the greater the relationship satisfaction, well-being and dyadic regulation as outcome variables [14]. Paying attention to the motivation to have a relationship in an SDT key provides additional information for the evaluation of relational functioning. For example, Gaine and La Guardia [11] demonstrated that a major relative autonomy is associated with more engagement, satisfaction, intimacy, and vitality in romantic relationships.

Sexual interactions can also contribute to happiness and improve the functioning of couples, as they result from the dynamics between intrapsychic and interpersonal processes [15]. Research on sexual motivation suggests that not all sexual experiences are adequately satisfying [16] and it is precisely in romantic relationships that sexuality is a key factor, as it shapes the quality of relationships [17]. Consequently, although romantic partners witness a physiological decline in sexual desire, keeping sexual motivations alive seems to be important for one’s personal well-being and for the improvement of one’s romantic relationship [18]. Sexual desire tends to reach its peak in the early phases of a relationship, as partners begin to know each other and become increasingly intimate and then decrease over time as they become more self-confident in the relationship [19, 20]. Investigating how sexual motivation can be revived to improve relationships is necessary, according to the results of some studies, which show a close connection between sexual and relational satisfaction [21].

Couple and sexual motivation are distinct in terms of their nature, function, and origin. However, they are interconnected in romantic relationships [11]. The emotional connection, psychological intimacy and stable bond fostered by couple motivation can strengthen the sexual aspect, while sexual motivation can reinforce the bond between partners [22]. Nevertheless, being in a relationship seems to satisfy the need for belonging, mutual support and personal growth more, which pertain to both individual and relational well-being. Conversely, sexual motivation appears to enhance vitality, pleasure and personal gratification more, although it also strengthens the sense of connection between partners.

These motivations are useful to understand why people are in relationships, what motivates them to stay together, and what can instead increase the risk conflict [3]. Motivation shapes the ways in which individuals manage their romantic relationships, for example in ways that are open, receptive and responsive to romantic partners, or alternatively in defensive ways that increase interpersonal conflict engagement, foster malaise and tension [11, 23]. According to SDT, autonomous motivation contributes to the satisfaction and psychological wellness of both partners in the dyad. Further, when a partner is more fully self-aware, self-expressive, and true-self-involved come with a number of advantages, and this includes investment in one’s relationships [3].

Motivation, conflict engagement and well-being

Autonomy in romantic relationships has been defined as motivation for growth but also as a tendency to face conflicts with less engagement [24]. Conflict engagement refers to all activities intended to address conflict. This is experienced as something negative, unwanted, and harmful and can lead to ignoring the reality of the conflict and its causes. Conflict engagement sees conflict as resulting from an inability to communicate authentically and productively, but when someone conflicts with their partner usually loses their control, insults them and says insignificant things [25, 26]. In this sense, conflictual dynamics can be determined by the partners’ dispositional motivations and in turn be a key aspect of well-being. Self-determination has been shown to have benefits for romantic relationships. For example, self-motivation is the most important factor in a good relationship and in being sexually involved with a partner [27]. It predicts better conflict management and, in turn, greater satisfaction following disagreement. The challenge for relationships is that partners have continually to negotiate decisions and rules, and when these are far from their expectations, they can trigger conflict and discomfort [3]. All couples must deal with conflict, in their everyday life [28–30]. During close relationships, partners are often expected to adapt to one another, negotiate how to share roles and responsibilities, redefine their ties to each partner’s family and peers, and engage in conflictual interactions [30]. However, what differentiates them is not the conflict itself, but the way in which the conflict is managed. Worse relational outcomes are generated by negative conflict management, such as experiencing conflict directly in terms of personal and acted out attacks, loss of control and insults [29, 30].

Conflict engagement is generally recognized as destructive especially due to the relational consequences it has between partners [28]. According to Killoren et al. [29], these negative ways of engagement in conflicts may exist in relationships from the very beginning but become more important over time; partners become motivated over time to further their relationship and invest in their romantic relationships [12, 23]. Furthermore, conflict engagement is often a stronger predictor in terms of relational outcomes compared to more positive resolution methods [29]. Prior works on relationship autonomy have largely focused on how it is associated with less defensiveness and fewer self-protective mechanisms [3, 31]; other studies have emphasized the mediating role of conflict engagement on relational satisfaction [32]. Accordingly, conflict engagement seems to mediate these processes and represents an important factor that predicts relational well-being and strongly contributes to individual happiness [24].

Set against this background, it may be easier for partners to engage in negative behaviours during conflict when they are respectively less motivated to be together and who in turn engage in less constructive behaviours for the relationship [32]. Therefore, it is likely that relationship and sexuality autonomy also promote desire to care for and support the partner, as well as the tendency to approach relationship conflicts with less anger, involvement, and engagement. These factors predict a higher quality of relationship. Further exploration of this topic further could provide valuable insights into how close relationships are maintained over time by demonstrating the role of different types of motivation in resolving conflict within dyadic relationships.

Adopting a dual perspective of individual and couples’ well-being allow us to distinguish between personal and couple happiness within romantic relationships. This is important because, although the two aspects are associated, they are two distinct and help to promote individual and couples’ adjustment [33]. Individual well-being is an expression of the fulfilment of happiness and pleasure, based on the expression of one’s virtues. For example, it involves having a positive attitude towards oneself and one’s past life, a sense of independence and self-determination, the ability to recognise one’s competence in managing one’s environment and external activities; and a positive attitude towards new experiences [34]. Couple well-being refers to an individual’s satisfaction with and perception of the stability of their relationship [35]. It is composed of different aspects, such as intimacy, mutuality, warmth, support and positive exchanges. Specifically, studies [33, 36] have shown that romantic relationships are characterised by a multidimensional nature implying closeness between partners. This closeness includes aspects relating to intimacy, the strength of the emotional connection and attachment to a partner, and feelings of appreciation, admiration and affection, as well as a sense of reliable alliance or ‘specialness’ with the partner. These aspects are fundamental within romantic relationships. In fact, dyads are characterised by their interdependence. As well as having their own experiences, one partner’s experiences can influence the other’s [37]. A growing number of studies show that, when studying couples, it is essential to use a dyadic approach that integrates the reciprocal associations between partners and individual aspects [38]. This is because a person’s characteristics influence their own outcomes, as well as their partner’s characteristics influencing their outcome.

The relationship, as the “need to belong”, refers to the tendency to be oriented towards forming strong and stable interpersonal bonds. For this reason, this research investigates couple dynamics according to a main approach: interpretation of and responses to conflict, and pathways to various forms of relationship functioning.

Despite the theoretical importance of motivation, few existing studies have examined relationship and sexual motivation together, or explored how they jointly influence conflict engagement, which is a key factor in romantic relationship well-being. Furthermore, while previous research has demonstrated that autonomy fosters intimacy and healthier interaction patterns, the manner in which different motivational orientations towards couple and sexual behaviours influence partners’ propensity to approach conflict with anger, defensiveness, or openness remains unclear. In addition, studies have recognised that partners’ individual motives contribute not only to their own outcomes, but also to each other’s. However, current literature lacks dyadic perspectives that capture how each partner’s motivation affects their own well-being and that of their partner [38]. These gaps limit our ability to understand the mechanisms through which motivation contributes to the functioning of relationships. Prior studies have predominantly focused on single motivational domains (e.g., general relationship autonomy or sexual motives), often overlooking how these motivational systems interact. Moreover, conflict engagement has typically been studied as a by-product of communication patterns or personality traits, rather than as an outcome shaped by the quality of motivation. By failing to consider the integration of couple motivation, sexual motivation, and conflict behaviour, past research has not fully captured the complexity of relational processes. A more comprehensive approach is necessary to understand why some couples experience escalating conflict and dissatisfaction even when they report positive relational intentions.

The present study

The dyadic context of romantic relationships provides a rich domain for extending the Self-Determination Theory. In line with the SDT, romantic relationships seem an important context for studying motivational dynamics and their satisfaction. The degree of relational autonomy, derived from high-quality motivations, predicts outcomes relating to relationships and individual well-being. This is because motivation is considered a driving force that can satisfy basic needs (e.g. autonomy, competence and relatedness). It also facilitates how couples’ approach and manages disagreements and conflicts [39].

For this reason, the current study aims to test: (a) direct associations from couple motivation and sexual motivation to conflict engagement both within and between partners; (b) direct associations from conflict engagement to individual well-being and couple well-being both within and between partners; (c) direct associations from couple motivation and sexual motivation to individual well-being and couple well-being both within and between partners; (d) indirect effects via conflict engagement as a mediator in the association between motivation and well-being. There are four hypotheses: (a) Couple motivation and sexual motivation are negatively associated with conflict engagement in both and across partners; (b) Conflict engagement is negatively associated with individual and couple well-being in both and across partners; (c) The relationship between motivation and well-being is positive in both and across partners; and (d) Conflict engagement mediates any direct association between motivation and well-being. Such efforts would not only analyse relationship development but would also improve knowledge of interpersonal processes with regard to managing self-determined functioning in a truly interdependent context [12].

Method

Participants and procedure

A total of 402 young adult couples with ages ranging between 20 and 30 years old (females: M = 22.80, SD = 2.64; males: M = 24.32, SD = 2.93) completed the entire questionnaire by meeting the following inclusion/exclusion criteria: (a) being older than 18 but younger than 30 years, (b) living in Italy, (c) being in a stable relationship for between 1 and 5 years and (d) they want to marry the partner in the future. These age ranges were selected because emerging adulthood has recently been described as a distinct developmental period spanning the ages of 18 to almost 30, when dating relationships often evolve into more serious romantic relationships [40, 41].

According to Kline [42], the sample has been estimated in terms of the ratio of the number of cases (N) to the number of model parameters requiring statistical estimates (q). A minimum recommended sample size-parameters ratio would be 20:1. Participants have been recruited from southern Italy, had Italian nationality, and Italian was their first language. Couples reported being in a relationship lasting between 1 and 5 years (M = 2.54, SD = 1.25). About couples’ education, most of them claim to have high school diploma (female 66%; male 72%), followed by those with some couples with a degree or post-graduate degree (female 32%; male 22%), and finally by ones with middle school diploma (female 2%; male 6%).

We used a snowball recruitment technique: psychology graduate trainees have solicited volunteers through personal knowledge, acquaintances, friends, and appeals to the local community and organizations in Sicilia and Calabria (Italy). Both members of the couples responded to a research protocol separately, under the supervision of a psychology graduate trainee, to ensure that partners of couples completed the measures independently and on their own. Participation has been voluntary, and no compensation has been provided. In accordance with the international guidelines of the 1964 Helsinki Declaration and its subsequent amendments or comparable ethical standards (IRM/Committee of CeRip of the University of Messina, Prot.n.92084 of 03/10/2019), the study received approval from the local ethics committee and only couples in which both partners signed consent forms have been allowed to participate in the study. At all stages of the research, participants’ privacy rights have been guaranteed in compliance with the law on privacy. At the time of filling out the protocols, the members of the couples have been assigned an anonymous identification code to link the data provided by both partners.

Measures

Couple motivation

Participants filled out the Couple Motivation Questionnaire (CMQ) [9]. The CMQ consists of 18 items (e.g., “Because I need to be in a relationship with my partner to feel important”) rated on seven-point Likert-type scale from 1 (not at all agree) to 7 (completely agree), presented after the item stem: “Please take a few moments to think about the reasons why you are currently in the relationship with your partner”. In this study, the Relative Autonomy Index (RAI) [43] has been used, a weighted calculation commonly used in SDT research as it allows to summarise the motivational orientations described along the SDT continuum. The formula used is as follows: (3 x intrinsic) + (2 x integrated) + (2 x identified) + (-1 x introjected) + (-2 x external) + (-3 x amotivation), where higher scores indicate higher quality of motivation (i.e., more autonomous motivation), and lower scores indicate lower quality of motivation (i.e., more controlled motivation). The Italian version of the CMQ was developed using the back translation method in combination with committed method [44, 45]. First, the instrument was translated from its original form. Then, to confirm the similarity of items, a back-translation procedure was used, in line with the recommendations of the International Test Commission [46]. Three separate individuals then translated the scale from English to Italian: an English professor, an Italian psychology professor and a psychology PhD student. They then discussed every difference and discrepancy between the two versions until an acceptable solution was found. Based on this work, a multilingual expert translator with no prior knowledge of the original versions back-translated the Italian version. The original version and the back-translation from Italian to English were found to be identical.

Previous studies have shown good psychometric characteristics for this scale [11, 31, 47]. Also in this study, the CMQ shows good psychometric properties (see Table 1).

Table 1.

Descriptive analyses and correlations

	Min	Max	M	SD	Ske	Kur	α	1	2	3	4	5	6	7	8	9	10
1. Individual Well-being Female	2.17	4.00	3.17	0.32	−0.28	−0.32	0.71	-
2. Individual Well-being Male	2.06	4.00	3.18	0.37	− 0.50	− 0.03	0.76	0.25**	-
3. Couple Motivation Female	-6.00	43.00	29.40	9.40	-1.22	1.49	0.75	0.33**	0.34**	-
4. Couple Motivation Male	-2.33	43.00	28.35	9.37	− 0.95	0.63	0.80	0.26**	0.49**	0.39**	-
5. Conflict Engagement Female	1.00	5.00	2.52	0.94	0.32	− 0.51	0.77	− 0.32**	− 0.25**	− 0.19**	− 0.21**	-
6. Conflict Engagement Male	1.00	5.00	2.26	0.92	0.59	0.00	0.75	− 0.25**	− 0.33**	− 0.26**	− 0.30**	0.34**	-
7. Couple Well-Being Female	2.40	5.00	4.65	0.50	-2.05	4.56	0.90	0.29**	0.27**	0.68**	0.31**	− 0.15**	− 0.24**	-
8. Couple Well-Being Male	2.60	5.00	4.66	0.49	-1.72	2.53	0.91	0.22**	0.43**	0.39**	0.67**	− 0.19**	− 0.28**	0.47**	-
9. Sexual Motivation Female	-18.00	43.00	26.57	9.88	-1.17	2.10	0.79	0.23**	0.11**	0.36**	0.19**	− 0.04	− 0.13**	0.28**	0.15**	-
10. Sexual Motivation Male	-2.75	43.00	27.88	8.41	-1.12	1.34	0.81	0.18**	0.25**	0.26**	0.45**	− 0.24**	− 0.24**	0.18**	0.34**	0.33	-

Note: n = 402

Ske Skewness, Kur Kurtosis

**p < .01

Sexual motivation

In order to measure participants’ sexual motivation, all the couples completed the Sexual Motivation Scale (SexMS) [48]. The SexMS consists of 24 items (e.g., “For the pleasure I feel when my partner stimulates me sexually”) rated on a Likert scale from 1 (not at all agree) to 7 (completely agree), presented after the item stem “There are many reasons why people have sexual relationships. Please indicate to what extent each of the statements below corresponds to your motives for having sexual relationships” and the Relative Autonomy Index (RAI) [43] has been used. The Italian version of the SexMS was developed using the back translation method in combination with committed method [44, 45].

Also in this study, the SexMS shows good psychometric properties (see Table 1) overlapping with those obtained in other researches [48, 49].

Conflict engagement

To measure the conflict engagement a subscale of the Conflict resolution inventory (CRSI) [25] has been used. The “Conflict engagement” subscale is a self-report instrument used to measure a specific conflict resolution strategy in couple relationships. The subscale allows to evaluate, with 4 items (e.g., “Launching personal attacks”) on Likert scale from 1 (never) to 5 (always), the frequency with which each member of the couple uses specific ways to deal with arguments or discussions with their respective partner, presented after the item stem “Rate how frequently you use the following ways to deal with arguments or disagreements with your partner”. The Italian version of the scale was developed using the back translation method in combination with committed method [44, 45]. Previous studies have extensively shown good psychometric characteristics for this scale [50–52] and further confirmed in this study (see Table 1).

Couple well-being

To assess couple well-being, the “closeness” subscale of the Italian version of the “Romance Qualities Scale” [36, 53] has been employed. The subscale uses five items (English sample item “Sometimes my partner does things for me, or makes me feel special”; Italian sample item: “Qualche volta il mio partner fa delle cose per me, che mi fanno sentire speciale”) on a Likert scale ranging from 1 (absolutely false) to 5 (absolutely true). Previous studies [36, 54] have demonstrated good psychometric characteristics of this scale, a satisfactory degree of generalizability, and internal consistency; internal consistency is also adequate in this study (see Table 1).

Individual well-being

To measure the individual well-being, all participants completed the Italian version of the Psychological Well-Being Scale (PWS) [55]. The self-report instrument in its short form consists of 18 items (e.g., “When I look at the story of my life, I am pleased with how things have turned out”) ranged on a Likert scale from 1 (I do not agree) to 4 (I fully agree). Previous studies [56] have clearly documented the psychometric characteristics of the PWS. In the current study, internal consistency is also adequate (see Table 1).

Data analysis

The data have been structured as dyadic data in an Excel dataset and then organised in a pairwise structure, where each line represented a dyad containing male and female scores. Full collinearity tests were performed using the WarpPLS 8.0 software to control for common method bias [57]. Descriptive statistics (mean, standard deviation, skewness and kurtosis), Cronbach’s alpha values, and Pearson correlations have been conducted using the Statistical Package for the Social Sciences (IBM SPSS Statistics 19), and Pearson correlations used for all scales of each questionnaire. Motivation has been operationalised by creating an RAI score in accordance with the procedure outlined in the Measure Section. At the scale levels, the total scores and parcels were created using the average of the items. All scores were created with at least three items, and there were no missing values at the scale level. To test and control for the effects of background variables, a multivariate analysis of covariance (MANCOVA) was conducted with all the study variables as dependent variables. This analysis included partners’ age, partners’ educational level, duration of the relationship, as covariates. For background variables that showed multivariate effects, subsequent univariate analyses and pairwise comparison adjusted with Bonferroni correction were conducted.

The open-source software R (version 4.1.0) with the implementation of the lavaan package has been used to conduct an analysis to test the hypothesized mediation model (see Fig. 1) with latent variables using SEM, robust maximum likelihood estimation which includes the Yuan-Bentler scaled χ2 index [58], and the actor–partner interdependence model (APIM) approach [59, 60]. The bootstrapping approach has been used to estimate the confidence intervals of the associations of the model, and in accordance with previous studies [61] 5,000 bootstrap replication samples were used. Before proceeding to examine the structure of the proposed model, a measurement model analysis (reliability, convergent validity, discriminant validity) was conducted.

Fig. 1.

Structural model

Note: Coefficients represent standardized values; only significant paths (p < .05) were reported. Circles represent the latent variables. For the sake of clarity, the parcels and items of the latent variables are not reported. Below is the structure of the latent variables. Couple well-being Female =~ Item 1 + Item 2 + Item 3 + Item 4 + Item 5. Couple well-being Male =~ Item 1 + Item 2 + Item 3 + Item 4 + Item 5. Individual well-being Female =~ Parcel 1 + Parcel 2 + Parcel 3. Individual well-being Male =~ Parcel 1+ Parcel 2 + Parcel 3. Conflict Engagement Female =~ Item 1 + Item 2 + Item 3 + Item 4. Conflict Engagement Male =~ Item 1 + Item 2 + Item 3 + Item 4. Sexual Motivation Female =~ Parcel 1 + Parcel 2 + Parcel 3 + Parcel 4. Sexual Motivation Male =~ Parcel 1 + Parcel 2 + Parcel 3 + Parcel 4. Couple Motivation Female =~ Parcel 1 + Parcel 2 + Parcel 3. Couple Motivation Male =~ Parcel 1 + Parcel 2 + Parcel 3

Results

Descriptive statistics and preliminary analyses

There are no missing values. EM estimates will not be calculated. All full collinearity variance inflation factors (VIFs) were below 3.3 (Table 2), indicating an absence of common method bias [57]. The descriptive statistics and correlations between all study variables are presented in Table 1. Examination of skewness and kurtosis level for the study variables has been conducted and considering a moderate violation of data normality for some variables, the bootstrapping standard errors have been used to provide parameters [62]. Preliminary analyses are conducted to test the role of the background variables in the study variables. A multivariate analysis of covariance (MANCOVA) was conducted and showed multivariate effects for female age, Wilks’s λ = 0.94, F(10, 381) = 2.51, p = .01, ηpš = 0.06, and male age, Wilks’s λ = 0.94, F(10, 381) = 2.93, p = .01, ηpš = 0.06. Subsequent univariate ANOVAs showed effects of female age on female couple motivation, F(1, 399) = 1.87, p=.05, ηpš=0.50, and on female sexual motivation, F(1, 399) = 9.01, p=.00, ηpš=0.02. With increasing age, women reported higher levels of couple motivation and lower sexual motivation. Male age had an effect on male couple motivation, F(1, 399) = 4.61, p=.03, ηpš=0.57, on female conflict engagement, F(1, 399) = 6.78, p=.01, ηpš=0.74, on female sexual motivation, F(1, 399) = 7.07, p=.01, ηpš=0.02, and in female individual well-being, F(1, 399) = 8.48, p=.00, ηpš=0.02. With increasing male age, men reported higher levels of couple motivation while women reported higher levels of female individual well-being and sexual motivation, and lower levels of conflict engagement.

Table 2.

Variance inflation factors

	VIF	Tolerance
Dependent variable: Individual Well-being Female
Couple Motivation Male	1.44	0.69
Sexual Motivation Male	1.41	0.71
Couple Motivation Female	1.35	0.74
Sexual Motivation Female	1.25	0.80
Conflict Engagement Male	1.24	0.81
Conflict Engagement Female	1.19	0.84
Dependent variable: Individual Well-being Male
Couple Motivation Male	1.44	0.69
Sexual Motivation Male	1.41	0.71
Couple Motivation Female	1.35	0.74
Sexual Motivation Female	1.25	0.80
Conflict Engagement Male	1.24	0.81
Conflict Engagement Female	1.19	0.84
Dependent variable: Conflict Engagement Female
Couple Motivation Male	1.40	0.72
Sexual Motivation Male	1.36	0.73
Couple Motivation Female	1.32	0.76
Sexual Motivation Female	1.24	0.80
Dependent variable: Conflict Engagement Male
Couple Motivation Male	1.40	0.72
Sexual Motivation Male	1.36	0.73
Couple Motivation Female	1.32	0.76
Sexual Motivation Female	1.24	0.80
Dependent variable: Couple Well-Being Female
Couple Motivation Male	1.44	0.69
Sexual Motivation Male	1.41	0.71
Couple Motivation Female	1.35	0.74
Sexual Motivation Female	1.25	0.80
Conflict Engagement Male	1.24	0.81
Conflict Engagement Female	1.19	0.84
Dependent variable: Couple Well-Being Male
Couple Motivation Male	1.44	0.69
Sexual Motivation Male	1.41	0.71
Couple Motivation Female	1.35	0.74
Sexual Motivation Female	1.25	0.80
Conflict Engagement Male	1.24	0.81
Conflict Engagement Female	1.19	0.84

Regarding the measurement model analysis, results are showed in Table 3. Although AVE should be higher than 0.5, the value of 0.4 is acceptable due to condition that if AVE value is less than 0.5, but composite reliability is higher than 0.6, the convergent validity of the construct is acceptable as reported by Fornell and David [59]. Convergent validity is achieved for every construct. With regard to discriminant validity, the recommendations are that the correlation coefficient is lower than 0.85. The reported results demonstrate factor correlations < 0.85, suggesting the absence of major complications, as supported by Henseler et al. [60].

Table 3.

Descriptive statistics (AVE, construct Reliability, latent Correlation)

Factor	AVE	1.	2.	3.	4.	5.	6.	7.	8.	9.	10.
1.Couple well-being female	0.44	(0.80)
2. Couple well-being male	0.47	0.54	(0.81)
3. Individual well-being female	0.46	0.36	0.28	(0.72)
4.Individual well-being male	0.52	0.32	0.55	0.33	(0.76)
5. Conflict engagement female	0.45	− 0.17	− 0.22	− 0.40	− 0.31	(0.76)
6. Conflict engagement male	0.45	− 0.28	− 0.33	− 0.32	− 0.40	0.44	(0.77)
7.Sexual motivation female	0.84	0.32	0.17	0.30	0.12	− 0.05	− 0.15	(0.95)
8.Sexual motivation male	0.76	0.20	0.40	0.22	0.30	− 0.26	− 0.28	0.36	(0.93)
9. Couple motivation female	0.70	0.83	0.46	0.42	0.41	− 0.25	− 0.31	0.41	0.30	(0.88)
10. Couple motivation male	0.72	0.34	0.79	0.31	0.61	− 0.24	− 0.36	0.20	0.49	0.44	(0.88)

Testing the mediation with path analysis

Structural Equation Modelling with latent variables was adopted and the model obtained is shown in Fig. 1. Results showed adequate fit for the data: 𝜒2(620) = 1179.81, p < .01, Y-B𝜒2(620) = 1098.67, p < .01, R-CFI = 0.94, SRMR = 0.05, R-RMSEA (90% CI) = 0.05 (0.04, 0.05).

As shown in Table 4, couple motivation is negatively associated with conflict engagement for female (β=-0.20) and male (β=-0.23). In turn, conflict engagement is negatively associated with individual well-being for female (β=-0.30) and male (β=-0.15). In addition, couple motivation is positively associated with individual well-being for female (β = 0.21) and male (β = 0.49), and couple well-being for female (β = 0.86) and male (β = 0.73). Female couple motivation is negatively associated with male conflict engagement (β=-0.17) and positively with male couple well-being (β = 0.14). Female sexual motivation is positively associated with individual well-being (β = 0.19) and male sexual motivation is negatively associated with female conflict engagement (β=-0.21). Among the indirect associations (Table 5), tested with the bootstrapping approach, significant paths are found from couple motivation to individual well-being by conflict engagement for female (β = 0.06) and male (β = 0.04), and from male sexual motivation to female individual well-being by female conflict engagement (β = 0.06) and from male sexual motivation to male individual well-being by male conflict engagement (β = 0.02). Finally, the covariances (all positive) are reported in Table 6.

Table 4.

Coefficients of the direct effects for the hypothesized model

Direct effect	b	p	95% CI		β
			CI.Low	CI.Upp
Couple Motivation F → Conflict Engagement F	-.11	.01	-.19	-.03	-.20
Sexual Motivation F → Conflict Engagement F	.06	.08	-.01	.12	.12
Couple Motivation M → Conflict Engagement F	-.04	.39	-.12	.05	-.07
Sexual Motivation M → Conflict Engagement F	-.12	.01	-.21	-.03	-.21
Couple Motivation M → Conflict Engagement M	-.13	.01	-.22	-.04	-.23
Sexual Motivation M → Conflict Engagement M	-.07	.13	-.16	.02	-.11
Couple Motivation F → Conflict Engagement M	-.10	.03	-.19	-.01	-.17
Sexual Motivation F → Conflict Engagement M	.00	.93	-.06	.06	.01
Conflict Engagement F → Individual Well-Being F	-.11	.00	-.16	-.05	-.30
Conflict Engagement M → Individual Well-Being F	-.02	.34	-.07	.02	-.07
Couple Motivation F → Individual Well-Being F	.04	.01	.01	.07	.21
Sexual Motivation F → Individual Well-Being F	.03	.01	.01	.05	.19
Couple Motivation M → Individual Well-Being F	.02	.12	-.01	.05	.12
Sexual Motivation M → Individual Well-Being F	-.02	.29	.04	.01	-.08
Conflict Engagement M → Individual Well-Being M	-.06	.05	-.12	-.00	-.15
Conflict Engagement F → Individual Well-Being M	-.04	.11	-.10	.01	-.10
Couple Motivation M → Individual Well-Being M	.11	.00	.07	.14	.49
Sexual Motivation M → Individual Well-Being M	-.01	.52	-.04	.02	-.04
Couple Motivation F → Individual Well-Being M	.03	.06	-.00	.07	.15
Sexual Motivation F → Individual Well-Being M	-.01	.42	-.03	.01	-.05
Conflict Engagement F → Couple Well-Being F	.03	.31	-.03	.10	.05
Conflict Engagement M → Couple Well-Being F	-.04	.32	-.11	.04	-.06
Couple Motivation F → Couple Well-Being F	.29	.00	.21	.37	.86
Sexual Motivation F → Couple Well-Being F	-.01	.74	-.04	.03	-.02
Couple Motivation M → Couple Well-Being F	-.01	.70	-.06	.04	-.03
Sexual Motivation M → Couple Well-Being F	-.01	.50	-.06	.03	-.04
Conflict Engagement M → Couple Well-Being M	-.02	.68	-.09	.06	-.03
Conflict Engagement F → Couple Well-Being M	-.01	.89	-.07	.07	-.01
Couple Motivation M → Couple Well-Being M	.24	.00	.18	.30	.73
Sexual Motivation M → Couple Well-Being M	-.00	.98	-.05	.05	-.00
Couple Motivation F → Couple Well-Being M	.05	.02	.01	.09	.14
Sexual Motivation F → Couple Well-Being M	-.01	.54	-.05	.02	-.04

Note: b = unstandardized regression coefficient

CI Confidence interval, LL Lower limit, UL Upper limit, β Standardized regression coefficient

** p < .01

Table 5.

Coefficients of the indirect effects for the hypothesized model

Indirect effect	b	p	95% CI		β
			CI.Low	CI.Upp
VIA Conflict Engagement Female
Couple Motivation F → Individual Well-being F	.01	.04	.00	.02	.06
Couple Motivation F → Couple Well-being F	-.00	.35	-.01	.00	-.01
Sexual Motivation F → Individual Well-being F	-.01	.12	-.01	.00	-.04
Sexual Motivation F → Couple Well-being F	.00	.37	-.00	.01	.01
Couple Motivation M → Individual Well-being F	.00	.39	-.01	.01	.02
Couple Motivation M → Couple Well-being F	-.00	.50	-.01	.00	-.00
Sexual Motivation M → Individual Well-being F	.01	.03	.00	.02	.06
Sexual Motivation M → Couple Well-being F	-.00	.34	-.01	.00	-.01
Couple Motivation F → Individual Well-being M	.01	.20	-.00	.01	.02
Couple Motivation F → Couple Well-being M	.00	.89	-.01	.01	.00
Sexual Motivation F → Individual Well-being M	-.00	.24	-.01	.00	-.01
Sexual Motivation F → Couple Well-being M	-.00	.89	-.00	.00	-.00
Couple Motivation M → Individual Well-being M	.00	.41	-.00	.01	.01
Couple Motivation M → Couple Well-being M	.00	.90	-.00	.00	.00
Sexual Motivation M → Individual Well-being M	.01	.19	-.00	.01	.02
Sexual Motivation M → Couple Well-being M	.00	.89	-.01	.01	.00
VIA Conflict Engagement Male
Couple Motivation M → Individual Well-being M	.01	.05	.00	.02	.04
Couple Motivation M → Couple Well-being M	.00	.68	-.01	.01	.01
Sexual Motivation M → Individual Well-being M	.00	.22	.00	.01	.02
Sexual Motivation M → Couple Well-being M	.00	.69	-.00	.01	.00
Couple Motivation F → Individual Well-being M	.01	.17	-.00	.01	.03
Couple Motivation F → Couple Well-being M	.00	.68	-.01	.01	.01
Sexual Motivation F → Individual Well-being M	-.00	.93	-.00	.00	-.00
Sexual Motivation F → Couple Well-being M	-.00	.93	-.00	.00	-.00
Couple Motivation M → Individual Well-being F	.00	.38	-.00	.01	.02
Couple Motivation M → Couple Well-being F	.01	.37	-.01	.02	.01
Sexual Motivation M → Individual Well-being F	.00	.41	-.00	.01	.01
Sexual Motivation M → Couple Well-being F	.00	.40	-.00	.01	.01
Couple Motivation F → Individual Well-being F	.00	.35	-.00	.01	.01
Couple Motivation F → Couple Well-being F	.00	.30	-.00	.01	.01
Sexual Motivation F → Individual Well-being F	-.00	.93	-.00	.00	-.00
Sexual Motivation F → Couple Well-being F	-.00	.93	-.00	.00	-.00

Note: b = unstandardized regression coefficient

CI Confidence interval, LL Lower limit, UL Upper limit, β Standardized regression coefficient

** p < .01

Table 6.

Covariances for the hypothesized model

	unst		95% CI		stand
Covariances		p	CI.Low	CI.Upp
Couple Motivation F ↔ Sexual Motivation F	.94	.00	.57	1.32	.41
Couple Motivation F ↔ Couple Motivation M	.90	.00	.59	1.22	.44
Couple Motivation F ↔ Sexual Motivation M	.57	.00	.30	.83	.30
Sexual Motivation F ↔ Couple Motivation M	.56	.00	.18	.74	.20
Sexual Motivation F ↔ Sexual Motivation M	.76	.00	.46	1.06	.36
Couple Motivation M ↔ Sexual Motivation M	.94	.00	.64	1.24	.49
Individual Well-Being F ↔ Couple Well-Being F	.00	.62	-.01	.02	.05
Individual Well-Being F ↔ Individual Well-Being M	.00	.39	-.01	.01	.07
Individual Well-Being F ↔ Couple Well-Being M	-.00	.92	-.01	.01	-.01
Couple Well-Being F ↔ Individual Well-Being M	-.00	.87	-.01	.01	-.02
Couple Well-Being F ↔ Couple Well-Being M	.04	.00	.02	.06	.55
Individual Well-Being M ↔ Couple Well-Being M	.01	.31	-.01	.02	.10
Conflict Engagement F ↔ Conflict Engagement M	.19	.00	.12	.27	.37

Note: Unst Unstandardized coefficient, Stand Standardized coefficient 

Discussion

Through the lens of Self-Determination Theory, this study offers new insights into the dynamics linking couple functioning and psychological outcomes, highlighting the relevance of motivation in romantic relationships challenged by conflict and tension.

The first objective of this study has been to verify whether the couple motivation and the sexual motivation are negatively associated with the conflict engagement in both and across partners. Partially supporting our hypotheses, the results indicate an association between couple motivation and conflict engagement. In line with the Self-Determination Theory, autonomous motivation appears to play a central role in how individuals manage conflict [2, 3] This is because autonomous motivation makes relationships more stable over time, and is associated with greater goal achievement and a more positive subjective experience when pursuing goals [1]. This pattern was observed for both men and women, suggesting that high-quality motivation benefits partners similarly across genders. When individuals are autonomously motivated to be in a relationship, their involvement is guided by personally endorsed values, interests, and preferences. This sense of self-approval reduces the likelihood of reactive and maladaptive conflict engagement, as partners feel more willingly invested in their relational activities [27].

Regarding cross-over effects, women’s couple motivation was negatively associated with men’s conflict engagement. The advantages of an autonomous motivation in responding to the conflict are not limited to one’s own autonomy but are also transferred to the partner. Feeling autonomous in the relationship can make the respective partner feel more authentic and unconditionally supported in how they behave, enabling them to manage conflict more spontaneously, with fewer arguments. On the other hand, it becomes easier to react to conflict with anger when one feels less autonomous and more controlled. In addition, male sexual motivation is associated with female conflict engagement. Studies have indicated that women tend to adopt a more emotional and interpersonal approach to sexuality [63]. They are more likely to live and care more about their romantic relationships, experiencing the sexual activity of the partner as a reflection of the quality of the relationship. Partner responsiveness is a central feature of autonomy support [39] and involves acknowledging a partner’s perspective [10]. When men act more autonomously in their sexual behaviours, their partners may interpret this interest in sex as a sign that their relationship is functioning well. This process may be more important for women than for men, as the literature suggests that women monitor their relationships more closely than men and experience greater frustration when problems arise [20]. Furthermore, male sexual motivation is associated with female conflict engagement. Studies have indicated that women tend to adopt a more emotional and interpersonal approach to sexuality [64]. They are more likely to live and care more about their romantic relationships, experiencing the sexual activity of the partner as a reflection of the quality of the relationship. Partner responsiveness is a central feature of autonomy support [3] and involves acknowledging a partner’s perspective [22]. When men act more autonomously in their sexual behaviours, their partners may interpret this interest in sex as a sign that their relationship is functioning well. This process may be more important for women than for men, as the literature suggests that women monitor their relationships more closely than men and experience greater frustration when problems arise [20]. In addition, this gender-specific pattern is consistent with previous research documenting differences in how men and women experience both sexuality and conflict [24]. From a Self-Determination Theory perspective, men may be more likely to express and regulate their sense of autonomy through the sexual domain, making autonomous sexual motivation particularly salient for their partners’ functioning. Indeed, men tend to engage more frequently in desired sexual behaviors and to act on their sexual autonomy more directly than women that tend to be more passive [65]. When sexuality is experienced as self-endorsed and oriented toward intimacy and connection—rather than obligation or control—it may serve a regulatory function in women’s conflict behavior. Men who are autonomously motivated sexually (i.e. to express love, intimacy and authentic desire) are less likely to use sex as a means of power, pressure, or reward, which in turn reduces tension and reactivity during relational conflicts [26]. In this sense, autonomous sexual motivation may buffer maladaptive conflict engagement by supporting more cooperative and less defensive responses when tensions arise.

In summary, the results confirm the findings of previous studies: a motivational approach is associated with positive conflict resolution [66]. However, this study identifies specific motivations and self-determination theory helps us to understand the underlying mechanisms.

Regarding the second objective, our hypotheses were only partially supported: conflict engagement was negatively associated with individual well-being. This negative association occurred when conflicts were expressed reactively, through arguments or intense discussions, consistent with previous research linking conflict engagement to satisfaction experienced within relationships [23, 33]. Individual well-being is strongly influenced by close interpersonal contexts, which can either support or hinder self-determination [12]. These findings align with the literature showing that intimate relationships primarily affect individual rather than relational well-being [67]. Conflict management impacts individual well-being because it involves emotions and the fulfillment of psychological needs. However, although this association emerged in the initial correlation, it disappeared in the final model. Although it seems reasonable that negative management of conflict can impact the relationship and increase the likelihood of perceiving the relationship as defective, other factors may also influence the well-being of couples in conflict situations. The lack of association with relational well-being may reflect the need for both partners’ active engagement; when only one partner uses constructive strategies, the positive effect may be limited to that partner’s personal well-being, without necessarily improving the overall quality of the relationship.

Regarding the third objective, positive direct associations have been found from couple motivation to individual and couple well-being of both partners, confirming the implications of Self-Determination Theory (SDT). Well-being also becomes an expression of social factors and sees good relationships as a resource for promoting optimal functioning [2, 3]. A high-quality romantic relationship offers great opportunities to develop a strong dyadic context, in which partners maintain a coherent and integrated sense of self [1], which promotes more authentic and self-determined reasons for being in the relationship and psychological well-being [3]. Partners with autonomous couple motivations experience greater personal well-being through the fulfilment of their own needs, as well as greater relational well-being through the pleasure they derive from caring for others, partly because they believe that this authenticates their sense of self, which in turn increases their personal well-being.

Although previous studies have reported stronger sexual desire and sexual motivation in men than in women [68], the results of this study suggest that sexual motivation is only associated with individual well-being in women. This result does not highlight that sexual motivation plays a different role in the well-being of men and women because sexuality ‘matters more’ to women, but rather because it is internalised and integrated into the self differently. According to SDT, individual well-being depends on the extent to which an experience fulfils one’s basic psychological needs. For many women, sexuality is an area in which they feel valued, experience emotional connection and develop a coherent sense of self [69]. Therefore, when sexual motivation is autonomous (i.e., driven by interest, pleasure or authentic desire), the sexual experience contributes directly to a sense of authenticity and personal integration, thereby increasing individual well-being.

With regard to crossover effects, the motivation of female couples is associated with the couple well-being of their partners. SDT helps to understand that voluntarily involving ourselves in a relationship because we consider it important and aligned with personal life goals (i.e. for autonomous reasons) has benefits not only for themselves, but also for their partner. Simply being in a relationship is not enough; partners must be committed to the relationship if it is to work well and increase their happiness and well-being [33]. Indeed, couple motivation implies taking care of a relationship partner’s needs, which should lead them feel responsive to their needs. This increases their relationship well-being, inspiring them to adopt a similar motivation in return. From an interdependence theoretical perspective, the presence of couple motivation may suggest that partners have undergone a transformation in their motivation, moving from considering only their own self-interest to considering the welfare of their partner and the relationship. In other words, when partners are more oriented towards their relationship, it suggests that they are motivated not only to benefit themselves, but also to benefit their partners and maintain the quality of the relationship — an approach that should benefits both partners [70].

Partially with the last objective, the conflict engagement of both partners has been found to mediate the associations between couple motivation and individual well-being, showing a common indirect effect. The reason why men and women perceive greater autonomy couple motivation in the relationship, experiencing greater individual well-being, is linked to the fact that their conflicts are not negatively acted out. These findings highlight that autonomous couple motivation alone does not produce well-being, but rather shapes the daily relational processes through which individual well-being is constructed or compromised. Conflict engagement is one such process, primarily reflecting individual self-regulatory processes during interpersonal stress. According to SDT, autonomous motivation implies that the relationship is experienced as a choice that is consistent with one’s values and an integral part of the self. This does not mean that partners do not experience conflict; rather, conflict itself is regulated differently. People with autonomous motivation are less defensive and reactive, and more open to dialogue when tensions arise. Conflict engagement encompasses reactive and dysfunctional modes of conflict management, such as yelling, intense arguments and emotional escalation. These modes frustrate basic needs, increasing stress and negative emotions and directly impacting well-being [32]. In other words, when the relationship is experienced autonomously, conflicts are less destructive and well-being is greater. However, this likely doesn’t impact relational well-being, as this depends on reciprocal and coordinated processes between partners. If only one partner is highly autonomous and manages conflict constructively, the benefits may be limited to that individual’s psychological well-being and may not enhance the relationship’s overall quality. Ultimately, it is found that the level of conflict engagement between both partners mediated the associations between male sexual motivation and the well-being of both men and women. This gender-specific pattern is consistent with previous research documenting differences in how men and women experience both sexuality and conflict [64, 68]. From a Self-Determination Theory perspective, men may be more likely to express and regulate their sense of autonomy through the sexual domain, making autonomous sexual motivation particularly salient for relational function of both partners. Indeed, men tend to engage more frequently in desired sexual behaviors and to act on their sexual autonomy more directly than women that tend to be more passive [65]. When sexuality is experienced as self-endorsed and oriented toward intimacy and connection—rather than obligation or control—it may serve a regulatory function in men and women’s conflict behavior. Men who are autonomously motivated sexually (i.e. to express love, intimacy and authentic desire) are less likely to use sex as a means of power, pressure, or reward, which in turn reduces tension and reactivity during relational conflicts [24, 32]. In this sense, autonomous sexual motivation may buffer maladaptive conflict engagement by supporting more cooperative and less defensive responses when tensions arise.

Limitations and future research recommendations

This study has a few limitations. First, due to its cross-sectional design, it does not allow to make predictions about the possible effects. Future studies should longitudinally follow or observe daily fluctuations in couple dynamics. Furthermore, our participants have been selected through convenience samples. Couples who choose to participate in the research may have more open and free attitudes towards their partners. In addition, because this study is limited to heterosexual couples, the results may not generalize to couples with different composition. Future research may replicate this model using a more heterogeneous sample and include additional demographic information to help contextualise the findings more effectively. The associations between the variables may be explained by additional variables, direct associations, or mechanisms that could not be tested in this model, but which may play a role. For instance, several studies have emphasised the mediating role of basic psychological needs (autonomy, competence, and relatedness) in the association between autonomous motivation and well-being outcomes [71]. Future studies may attempt to integrate and extend these findings. Finally, this study used self-report measures and some associations which were obtained may be biased, such as social desirability. In the future, it may be beneficial to promote the use of various methodologies alongside self-report instruments. The latter are valuable for investigating subjective perception. These methodologies could include observations or interviews, which are useful for comparing results obtained on the same dimension.

Practical implications

This research extends the understanding of the applicability of SDT that have important implications for clinical practice, couple counseling, and relationship education: being autonomously motivated is associated with more positive relationship outcomes, less likelihood of engaging in destructive behaviours, and greater well-being outcomes. These findings suggest that interventions to promote couple well-being do not focus exclusively on conflict resolution. Intervention such as profile motivation in compliance with SDT would be desirable as spaces for developing appropriate levels of autonomous motivation to both maintain a romantic relationship and share sexual intimacy with one’s partner. Interventions aimed at improving relationship quality may benefit from explicitly targeting the quality of partners’ motivation for being in the relationship and for engaging in sexual intimacy, rather than focusing solely on communication skills or conflict resolution techniques. Helping partners reflect on and internalize more autonomous reasons for maintaining their relationship—such as shared values, emotional closeness, and mutual growth—may reduce maladaptive conflict engagement and support individual well-being. Beyond clinical settings, the present findings also carry broader implications for relationship education and social policy. Programs aimed at promoting relational well-being—such as premarital education, family services, and public health initiatives—should incorporate motivational frameworks that emphasize autonomy, authenticity, and mutual support.

Theoretical implications

SDT describes close relationships as being central to human life and experience. This is because such relationships provide social support, happiness and well-being, and act as a buffer against stress. Therefore, maintaining a satisfying relationship is essential. Our findings also contextualise these aspects within the specific life stage of emerging adulthood. During this period, emerging adults are most likely to explore a variety of possibilities, particularly about the areas of love [72]. The main developmental tasks that emerging adults must face include building satisfactory romantic relationships [41]. In line with these aspects, this study aims to identify SDT factors that promote well-being and the underlying mechanisms. Specifically, motivational processes may be key to maintain relationships and to engage conflicts. Consistent with other research [3], autonomous reasons for being in the relationship, for both partners, would be associated with one’s own responses to conflict, which would in turn be associated with one’s well-being. Both results suggest that more autonomous motivations are associated with fewer negative interpersonal problems. In fact, when people feel autonomous, they are less involved in negative ways to manage a conflict [31]. While previous studies have emphasised the impact of conflict on couples’ well-being and how autonomous motivation in romantic relationships fosters less defensiveness, greater understanding during conflict, and higher satisfaction [3], this study highlights the importance of viewing relational challenges as opportunities for development.

In summary, this study contributes to Self-Determination Theory (SDT) by broadening its scope to include the dyadic and conflictual processes of romantic relationships. While previous SDT-based research has primarily examined individual outcomes or general relationship satisfaction, the current findings emphasise that motivation is a relational process that influences how partners interact with conflict and, consequently, perceive well-being. By incorporating both couple and sexual motivation within the same model, the study provides a more nuanced understanding of motivational dynamics, demonstrating that distinct yet interconnected motivational systems jointly influence relational functioning. Furthermore, the use of a dyadic framework emphasises the interdependent nature of motivation, conflict engagement and well-being. Identifying crossover effects supports SDT’s relational assumptions, showing that autonomous motivation benefits not only the individual, but can also protect partners from negative conflict behaviours and psychological outcomes. These findings suggest that motivation should be conceptualised as a shared relational resource operating within interpersonal systems, rather than merely as an individual disposition. Finally, by presenting conflict engagement as a motivationally driven process rather than merely a communication deficit or a personality trait, this study improves theoretical models of relationship functioning and emphasises the important role of motivational quality in explaining why conflicts escalate or remain manageable.

Conclusions

In line with Self-Determination Theory, this study highlights the central role of autonomous couple and sexual motivation in shaping conflict engagement and well-being within romantic relationships. By adopting a dyadic perspective, these results advance current relational models by identifying motivational quality as a key mechanism underlying adaptive conflict regulation and well-being.

Authors’ contributions

MG: Conceptualization, Methodology, Formal analysis, Data Curation, Writing - Original Draft. FL: Conceptualization, Data curation, Writing - Review & Editing preparation. FC: Formal analysis, Visualization, Supervision. MCG: Data Curation, Writing - Review & Editing, Supervision. All authors take responsibility for the integrity of the data and the accuracy of the data analysis. All authors contributed to and have approved the final manuscript.

Funding

University research funding.

Data availability

The data and the code that support the findings of this study are available from the corresponding author upon request.

Declarations

Ethics approval and consent to participate

In accordance with the international guidelines of the 1964 Helsinki Declaration and its subsequent amendments or comparable ethical standards, the study received approval from the local ethics committee (IBM/Committee of CeRip of the University of Messina, Prot. n. 92084 of 03/10/2019) and only couples in which both partners signed informed consent were allowed to participate in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.