It is a big and ambiguous question whether relations are for people or people are for relations. One of partners may say: “I am unhappy and I want to leave you for somebody else”. The other one replies: “No, you can’t. You must stay with me, as family is more important than happiness”.
Why is family more important? It is just a shell, especially if there are no children there. But it seems to be impossible to treat the question logically. Something tells me that a person can be put on one scale, and relationship values on another scale, and they will balance each other. Why so? It is because relations are a form of interaction of people, a way to exchange what they have, a way to support each other, to be together.