“Is Spousal Similarity for Personality A Matter of Convergence or Selection?”, 2010 (; backlinks):
We investigated whether spousal similarity for personality traits results from convergence (ie. couples becoming more similar to one another over time) or selection (ie. individuals selecting partners with similar traits) in a sample of 1,296 married couples. Personality was assessed using the Multidimensional Personality Questionnaire. We evaluated whether similarity increased with increasing length of marriage.
Evidence of spousal convergence was inconsistent across analyses, arguing against this mechanism as a compelling explanation for spousal similarity.
Accordingly, selection processes may better explain spousal similarity in these data. The one exception might be for aggressive aspects of personality.