Personality trait similarity in recently cohabiting couples: Partner choice, convergence, or selective breakup?

Romantic partners tend to be more similar in self-reported personality traits than would be expected by chance. This similarity can be due to the choice of a similar partner, partners becoming more similar to each other over time, or dissimilar couples breaking up. To examine whether these processes (choice, convergence, or breakup) explain personality trait similarities in couples, we followed a sample of 1,180 German couples (N = 2,360 individuals; age range = 17-82 years old) from right after moving in together (ranging from 0 to 4 years after) up to 16 years thereafter. Using bivariate latent growth curve models, we found that couples were already similar in openness, conscientiousness, extraversion, and agreeableness in the first years of moving in together. Although couples showed correlated change in conscientiousness, this did not increase similarity. Response surface analyses showed that separation risk was generally unrelated to dissimilarity. Furthermore, romantic partners did not become more dissimilar in the years before separation. Taken together, these results suggest that personality similarity in cohabiting couples is fully driven by choosing a similar partner. We discuss the implications of these findings for theory and research on personality similarity in romantic relationships. (PsycInfo Database Record (c) 2025 APA, all rights reserved).