The present two-study research examined the link between problematic pornography consumption, relationship satisfaction and sexual satisfaction by considering malleability beliefs about sexual life. In Study 1, the Sex Mindset Scale was created which measures beliefs about the changeability of sexual life. Exploratory Factor Analyses (N 1 = 755) indicated a one-factor structure, Confirmatory Factor Analyses (N 2 = 769) consolidated the previously established factor structure and the measure was reliable. In Study 2 (N 3 = 10,463), structural equation modeling (SEM) was used to explore the associations between gender, sex mindset, problematic pornography use, relationship and sexual satisfaction. The examined model showed that growth sex mindset had moderate positive association with sexual satisfaction and relationship satisfaction while problematic pornography use only showed a negative, but weak one. According to the present results, beliefs about the malleability of sexual life play a more important role in relationship satisfaction and sexual satisfaction than problematic pornography use. Moreover, sex mindset was negatively associated with problematic pornography use indicating that growth sex mindset can reduce the extent of problematic pornography consumption. In sum, sex mindset can be considered as an underlying pervasive sexuality-related implicit theory that can influence the individual's topic-relevant thinking and behavior through different pathways.