Chemsex refers to the use of psychoactive drugs for sexual purposes—before or during sex. This phenomenon mainly affects men, in particular those belonging to the LGBTQIA+ (lesbian, gay, bisexual, transgender, intersex, queer/questioning, asexual, and more diverse individuals) community. From the perspective of the transactional theory of stress, chemsex can be considered a strategy for coping with stress, which is why it is also extremely important to verify its role in functioning outside the sexual sphere. For this reason, this study verified the relationship between the use of chemsex, perceived stress, sexual well-being, and life satisfaction in young Polish men. The study involved 175 men (67 people using chemsex and 108 people in the control group) between 18 and 33 years of age. The Perceived Stress Scale, the Short Scale of Sexual Well-being, the Satisfaction with Life Scale, and the authors’ questionnaire about the use of chemsex were used. It was observed that individuals using chemsex showed a significantly lower level of sexual well-being and satisfaction with life (moderate effects) and a higher level of perceived stress (strong effect) when compared to the control group not using psychoactive substances. Additionally, a positive and moderate relationship was observed between the number of psychoactive substances used and perceived stress in the group of individuals using chemsex. Moreover, the number of substances used and the level of perceived stress were negatively and moderately related to the level of well-being in these individuals. It was also shown that perceived stress was a significant predictor of the number of psychoactive substances used before and during sex and that perceived stress and the number of psychoactive substances used were significant and negative predictors of life satisfaction and sexual well-being, explaining a large portion of their variance.