Using nationally representative data from India’s National Family Health Survey (NFHS-5, 2019–21), this study examines marital sexual entitlement, operationalized as men’s endorsement that a husband is justified in using force to have sex when a wife refuses. Weighted analyses were restricted to currently married/in-union men and excluded “don’t know/depends” responses on the outcome to enable interpretable comparisons. The primary exposure was recent non-spousal partnering in the past 12 months, coded as reporting at least one sexual partner other than a spouse during that period. Multivariable logistic regression assessed whether recent non-spousal partnering was associated with endorsement of forced sex within marriage/union, adjusting for violence-supportive norms (wife-beating justification), beliefs about women’s sexual refusal autonomy (e.g., whether refusal is justified under specified conditions), and patriarchal attitudes reflecting gendered power and control within intimate relationships. In the base model ( N = 55,588), recent non-spousal partnering was associated with higher odds of endorsing forced sex within marriage/union (adjusted odds ratio [AOR] = 1.45, 95% CI [1.17, 1.79]). In an extended model including patriarchal attitude measures ( N = 53,351), the association remained statistically significant (AOR = 1.32, 95% CI [1.05, 1.65]), alongside strong associations with violence-justifying and patriarchal beliefs. Findings suggest that endorsement of forced sex is embedded within broader coercion-accepting and patriarchal normative systems. Prevention efforts should treat marital sexual entitlement as part of a wider constellation of beliefs that legitimize coercion and violence within unions, integrating consent-centred, gender-transformative approaches within sexual and reproductive health and intimate partner violence services and supporting community norm-change strategies that strengthen recognition of women’s sexual refusal autonomy.