Expanding together: How self-expansion and partner responsiveness shape sexual well-being in couples coping with sexual interest/arousal disorder.

Sexual interest/arousal disorder (SIAD) is the most common sexual dysfunction among women, often leading to psychological and relationship difficulties for affected individuals and their partners. Although interpersonal dynamics are widely recognized as central to the etiology and maintenance of SIAD, dyadic studies are rare. 1 cross-sectional study found that women with SIAD experience lower levels of self-expansion in their relationships (new and broadening experiences), despite it being associated with improved sexual and relationship outcomes. However, single-time-point studies cannot capture meaningful within-person fluctuations or explain the mechanisms underlying how relational self-expansion is linked to better outcomes, such as partner responsiveness. This study investigated whether within-person fluctuations in self-expansion-daily and longitudinally-were linked to changes in perceived partner responsiveness (PPR), and in turn, sexual desire, satisfaction, and distress. Individuals with SIAD and their partners (n = 263; Mage = 34.67; SD = 10.26) completed daily surveys over 56 days (n = 228) and assessments at baseline, 6-, and 12-month follow-ups. On days when either partner reported more self-expansion than usual, both reported greater PPR, which was, in turn, linked to higher sexual desire and satisfaction, and lower sexual distress for both partners. Longitudinally, greater self-expansion than usual was associated with higher sexual desire and lower sexual distress for individuals with SIAD via their own PPR, and greater sexual satisfaction for both partners via partners' PPR. Findings support interpersonal models of SIAD and suggest that enhancing self-expansion and PPR could be valuable therapeutic targets for couples coping with SIAD. (PsycInfo Database Record (c) 2026 APA, all rights reserved).