Recent studies show that sexual approach (SA) motives, i.e., having sex to achieve a positive state such as sexual pleasure, are associated with higher sexual and relationship satisfaction. However, mechanisms linking SA motives to these outcomes are poorly understood, and the important distinction between SA motives that are self-directed (e.g., self-gratification) and other-directed (e.g., pleasing one's partner) has received little empirical attention, particularly in the everyday context of couples' sexuality. The present study focused, at an event level, on the associations between self-directed and other-directed SA motives, and sexual satisfaction and perceived partner responsiveness (PPR, an aspect of relationship intimacy). We also examined the mediating role of the couple's sexual behavior in these associations. Data were collected over a month-long daily diary study involving 35 newlywed heterosexual couples and analyzed using the Actor-Partner Interdependence Model. Results showed that men and women's self-directed SA motives were associated with their own higher sexual satisfaction and, in men, with their female partners' sexual satisfaction as well. For both men and women, these associations were mediated by sexual behavior: Self-directed SA motives were associated with more genitally focused sexual behavior (e.g., vaginal intercourse, oral sex), in turn associated with higher sexual satisfaction. For men, other-directed SA motives were associated with their own greater PPR and with that of their female partners. For women, self-directed SA motives were associated with their own greater PPR and with that of their male partners. Sexual behavior did not mediate associations with PPR. Theoretically, these findings support dyadic models of sexual satisfaction and intimacy and indicate that self-directed SA motives may be more important to sexual satisfaction than other-directed motives. Clinically, they support sex therapy approaches that integrate both partners and suggest that sexual motives and behavior may be relevant targets for intervention.