How do people believe they can best maintain sexual satisfaction in their romantic relationships? In the current research, we draw upon the literature on implicit theories of relationships to develop and validate a scale examining 2 types of lay beliefs about how sexual satisfaction can be maintained over time. Individuals high in sexual growth beliefs think that sexual satisfaction is attained from hard work and effort, whereas individuals high in sexual destiny beliefs think that sexual satisfaction is attained through finding a compatible sexual partner. Across 6 studies (2 cross-sectional online studies, a 21-day daily experience study, 2 dyadic studies, and an experimental manipulation; N = 1,896), we find evidence that those higher in sexual growth beliefs experience higher relationship and sexual satisfaction, and have partners who are more satisfied. Conversely, the effects of sexual destiny beliefs on satisfaction are contingent upon signs of partner compatibility: When individuals high in sexual destiny beliefs experience greater sexual disagreements in their relationship, they experience lower relationship quality. These results are independent of general relationship implicit beliefs, providing evidence for the uniqueness of these 2 constructs and the importance of examining implicit beliefs in the domain of sexuality. Overall, these results provide novel evidence that individuals’ lay beliefs about maintaining sexual satisfaction are important for understanding the quality of their sex lives and relationships.