New parent couples often experience fluctuations in postpartum sexual satisfaction, with body image concerns being a significant factor. While these concerns are linked to decreased sexual satisfaction, potential protective factors remain underexplored. In this study, we examined the moderating role of perceived partner support in the longitudinal links between new parents' own body image concerns and both their own and their partner's sexual satisfaction. Couples (n = 184) completed online validated questionnaires at 8 (T1), 12 (T2), and 24 (T3) months postpartum. A dyadic latent growth curve analysis based on the Actor-Partner Interdependence Model revealed a positive association between perceived partner support and sexual satisfaction at T1 for both parents, but no associations with the parents' sexual satisfaction trajectory. Two moderations were found: first, only when non-bearing partners received high levels of support, their own body image concerns were associated with their lower sexual satisfaction at T1. Second, only in bearing mothers receiving high levels of support, their own body image concerns were associated with a smaller decrease in their partners' sexual satisfaction from T1 to T3. Findings provide nuanced insights into partner support and sexual satisfaction among new parents, aiding in the development of targeted interventions.