How Do Couples Create Compatibility?

Paul Eastwick, a psychologist at the University of California, Davis, says compatibility is tightly tied to history: the story two people share and how that story evolves over time. Couples create compatibility. They do not find it by locating a partner who checks every box.

In a long relationship, romantic or otherwise, people build rituals, in-jokes, customs, and patterns. Two people are like saplings that grow together, entwining and supporting one another. After 10 years they look compatible, but the fit was grown. Predicting how the growth will go is very difficult before the two people sit down and do the work.

Research asks people to report rituals, stories, and in-jokes, sometimes called a tiny culture of the relationship. On days when people lean into the culture, they are happier in the relationship. The gain is separate from spending time together or doing fun things. It comes from remembering and revisiting the shared story, the in-jokes, and what the pair has constructed. The pattern is a central part of what a relationship is, and easy to miss.