<p>Current literature suggests that physical exercise may positively impact the quality of romantic relationships, though the mechanisms underlying this link remain unclear. This cross-sectional study examined (1) body image as a mediator between physical exercise and romantic relationship satisfaction, and (2) exercise motives as a moderator of this mediation, specifically whether health/fitness motives amplify the association between physical exercise and body image. A sample of 392 cisgender females aged 18–58 (<i>M</i> = 24, <i>SD</i> = 7.02) in opposite-gender romantic relationships was recruited. Mediation and moderated mediation analyses were conducted using PROCESS Macro in SPSS. Results showed that the health and fitness evaluation component of body image mediated the relationship between physical exercise and romantic relationship satisfaction. As such, increased physical exercise was associated with improved health and fitness evaluation, which in turn predicted greater romantic relationship satisfaction. Although health/fitness-related motivation did not moderate the hypothesized mediation path, the link between exercise frequency and health/fitness evaluation was stronger for women with higher health/fitness-related motivation compared to lower health/fitness-related motivation. These findings provide initial evidence of an indirect association between physical exercise and relationship satisfaction via health and fitness evaluation and support empirical and theoretical literature suggesting exercise motivation influences associations between exercise and body image. Overall, the health and fitness evaluation domain of body image may represent a key intervention target, potentially improved through participation in physical exercise.</p>