Table 1.

Focus of the lessons, underlying theories and example exercises of Hold on, for each other

Lesson	Focus	Underlying theories	Example exercise
Coping with your emotions	Focus on emotional consequences of being a partner of a cancer patient. Partners learn how to recognize, allow and express their emotions.	Acceptance, Self-compassion/Mindfulness	How often do I put on a brave face? Description: We asked partners to write down emotional situations they have experienced, how they felt at that moment when the situation occurred and how they coped with it. Aim: To help partners to become aware of their own emotions and their coping mechanisms. Are they regularly putting on a brave face and suppressing their emotions?
Your resilience-plan – how can you keep going?	Focus on resilience. Partners learn how to manage a period of chronic stress and to improve their resilience.	Acceptance, Self-compassion/Mindfulness	How much do you demand of yourself? Description: We asked partners to write down how many hours they work, sleep, and have leisure time each week. Aim: To show partners how much they demand of themselves and if their planning is realistic.
My mind works overtime	Focus on worrying and negative thoughts. Partners learn how to cope with dysfunctional thoughts.	Cognitive defusion (changing relationship with thoughts), Self-compassion/Mindfulness	Name your thoughts. Description: We asked partners to write down the five most often occurring thoughts that are associated with the disease of their partner. Afterwards, they are asked to read the thoughts aloud and to pay attention for what he/she experiences. Then they are asked again to read the thoughts aloud but now with the addition “I have the thought/ feeling that…”. They are asked again what their experiences are. Aim: To help partners create a greater distance between their thoughts and themselves, and to show them that thoughts are not necessarily a reflection of reality.
What is now really important?	Focus on values in life and relationships. Partners learn about their personal values and how to live in accordance with those values.	Values, Self-compassion/Mindfulness	Values in your relationship. Description: We asked partners to write down those things in their relationship that they value the most. Aim: To make them aware of things that are not congruent with their values. Are there things that should be different? Is it worth investing in their relationship? What can they do to bring their actual life choices closer?
Afraid, tired and moments of joy	Focus on positive things in life and their relationship. Partners learn about how important moments of joy and positive emotions are in this difficult period in their lives.	Committed action, Self-compassion/Mindfulness	Celebrate your relationship. Description: We asked partners to choose activities (e.g., write a love letter, have dinner at their favourite restaurant). Aim: To make them aware of how precious their relationship is and how to live in accordance with their values.
The art of communication	Focus on communication. Partners learn how to improve their communication skills.	Communicating about what really matters, Self-compassion/Mindfulness	What would you like to talk about? Description: We asked partners to write down topics they have discussed lately with their partner, topics that have not yet been discussed, and - if so - why these topics have not yet been addressed. Aim: To stimulate partners to communicate about the things that really matter.
Optional Lessons
Moving on with life	Focus on challenges that can occur after a successful cancer treatment. Partners learn how to cope with these upcoming challenges.	Acceptance, Cognitive defusion (gain control over thoughts), Values, Self-compassion/Mindfulness	Increase your hope. Description: We asked partners to imagine the situation in which their partner is cancer free for almost a year, and that he/she is feeling all right. They - as a partner - have done everything possible to cope with the situation. They have accepted it, and they are moving on with life. We ask them to imagine how life might be under these conditions. Aim: To show them that it sometimes can be helpful to create some distance and to have a closer look at their situation from a different point of view.
A good last period	Focus on topics related to the terminal phase of the patient. Partners learn what they can do in order to have a good last period with their ill partner.	Acceptance, Communicating about what really matters, Committed action, Self-compassion/Mindfulness	Beautiful memories. Description: We asked partners to think about (alone or with their partner) what they can do to produce new memories (e.g., things to experience together, trips or activities to make). Aim: To synthesise various aspects previously explored. To accept the development of the disease, talk about what really matters at that particular moment, commit to values and live in accordance with them.