Psychometric evaluation of the Persian version of the sexual motivation scale (SexMS) in Iranian married men and women

Sexual motivation plays a crucial role in intimate relationships and overall sexual health. The Sexual Motivation Scale (SexMS), developed by Gravel et al. (2016), assesses multidimensional types of sexual motivation based on self-determination theory. This study evaluated the psychometric properties of the Persian version of the SexMS among Iranian married adults. In this cross-sectional methodological study, the original 24-item SexMS was translated into Persian using a standardized forward–backward translation protocol. Face and content validity (CVR, CVI) were evaluated by an expert panel. A total of 394 married adults aged 18–60 years were recruited from health centers in Mashhad, Iran. Participants completed a demographic questionnaire and the Persian SexMS. Factorial validity was evaluated using Confirmatory Factor Analysis (CFA). Internal consistency (Cronbach’s alpha and McDonald’s omega) and test–retest reliability (two-week interval via Intraclass Correlation Coefficient [ICC]) were also assessed. The Persian SexMS demonstrated satisfactory content validity (CVI = 0.87, CVR = 0.89). In the initial CFA, one item from the Intrinsic Motivation subscale (Item 4) was removed due to a low factor loading (< 0.30). The re-specified six-factor model with 23 items demonstrated an acceptable fit to the data: χ²/df = 2.83, CFI = 0.90, IFI = 0.90, and RMSEA = 0.068 (90% CI: 0.061–0.076). Internal consistency was supported (Cronbach’s α = 0.868, McDonald’s ω = 0.882), and test–retest stability was strong (ICC = 0.87, p < 0.001). Integrated regulation yielded the highest mean score (21.49 ± 5.44), whereas Amotivation scored the lowest (7.14 ± 4.74). The 23-item Persian version of the SexMS demonstrates acceptable factorial validity and reliability, serving as a psychometrically sound instrument for research, assessment, and counseling contexts among Iranian married adults.