This capstone advances the theoretical claim that sexual integration is a fundamental aspect of positive psychology’s central aim of well-being. Despite positive psychology’s focus on flourishing, sexuality has largely been excluded from its research and practice. Drawing on differentiation theory, self-determination theory, and the PERMA framework, this project defines sexual integration as the core mechanism linking sexual experience to well-being. The paper argues that sexual integration—the internal alignment of one’s sexual self with values, identity, and beliefs—is a foundational condition for sustainable sexual flourishing when bounded within positive psychology’s PERMA framework. Given this framework, the capstone reviews empirical literature on optimal sexual experience, examining cultural barriers including pornography and sexual scripts, and proposes that the disconnection between desire and identity undermines sexual agency. An original Sexual Integration Scale is introduced, and the paper presents untested Positive Psychology Interventions (PPIs) designed to foster sexual integration. By positioning sexual integration as a central, rather than peripheral, aspect of psychological flourishing, this capstone invites researchers, practitioners, and communities to claim sexuality as a generative, congruent dimension of flourishing. In doing so, it calls for positive psychology to include the sexual self within its science of what makes life worth living.