Introduction: There has been significant changes over the last few decades in alcohol consumption levels and attitudes towards sexual relationships. Research and policy on the alcohol-sex mix are dominated by young people and ‘risk groups’, so this thesis explores the relationship in adults aged 25+ years. Methods: This PhD has two components, a systematic review and an ethnographic study undertaken within a sexual health service in England. Results: Results of both the systematic review and the ethnographic study found that the alcohol-sex mix continues through the life-course and can feature at key transition points, such as divorce. Those aged 25+ years can use alcohol in sexual situations in similar ways to younger people – to increase confidence, enhance pleasure and use it as an excuse to escape and experiment. However, results also found that similar to young people, those aged 25+ years experience similar negative outcomes, such as STIs and regret. However, this was further confounded in the ethnographic study, where for some patients attendance at the clinic highlighted a conflict between desire and morality. The clinic was more akin to a religious ceremony, where shame and guilt emerged in the search for moral recovery. Conclusion: The traditional stereotypes of the alcohol-sex mix afforded only to the young or promiscuous is outdated. Indeed, the relationship is more cyclical with partnership status and partner-level interactions a key defining factor rather than age.