Abstract
A growing body of literature suggests that specific markers of relationship quality are meaningfully linked to health outcomes. We tested whether relational self-expansion potential might be one of these markers in cross-sectional samples of individuals and romantic couples. Study 1 found that greater self-expansion potential was linked to better perceived physical health via both higher positive affect (PA) and lower negative affect (NA). Study 2 replicated these findings for PA (but not NA) and revealed both actor and partner effects of self-expansion potential. Results remained robust when statistically accounting for gender, age, body mass index, agreeableness, neuroticism, and perceived partner responsiveness. These findings identify a new relationship-level "active ingredient" associated with health and have implications for future physical health studies.