Personality disorders (PDs) are inherently associated with deficits in relating to other people. Previous research has shown consistent negative associations between categorical PD symptoms and relationship satisfaction. The present studies extend on these findings by examining the role of maladaptive traits in a number of ways. Self- and partner-reported maladaptive traits of both partners are included. Moreover, the present studies add a couple-centered approach by investigating the effects of actual similarity, perceptual similarity, and perceptual accuracy of the maladaptive trait profile on relationship satisfaction. PDs are conceptualized using 2 dimensional maladaptive trait models, that is, the Dimensional Assessment of Personality Pathology—Basic Questionnaire in Study 1 and the Personality Inventory for DSM–5 in Study 2. A total of 167 heterosexual couples participated in Study 1 and 52 heterosexual couples in Study 2. The actor–partner interdependence model was used to examine the associations between traits and relationship satisfaction, whereas the coefficient of profile agreement was used for the couple-centered analyses. Overall, results showed that the presence of maladaptive traits within romantic relationships has a detrimental effect on relationship satisfaction. Self-ratings on maladaptive traits, how we perceive our partners, and how we are perceived by our partners on maladaptive traits make significant contributions to our relationship (dis)satisfaction. Among the maladaptive traits, negative affect and detachment were most consistently negatively associated with relationship satisfaction. The couple-centered perspective showed less explanatory value but nontrivial associations between perceptual similarity and relationship satisfaction were found in Study 2.