In Western societies, a substantial proportion of the adult population does not have an intimate partner. The current paper puts forward an evolutionary theoretical framework, where people stay single for three main reasons, namely the mismatch between ancestral and modern conditions has resulted in several individuals lacking the adaptations necessary for attracting and retaining mates, individuals can increase their fitness by opting out of relationships, and individuals have constraints that prevent them from attracting a mate. The paper attempted to identify the reasons that drive men to be single and to investigate whether they were consistent with the proposed theoretical framework. More specifically, 13,429 responses from a recent Reddit thread were analyzed, and 6794 responses were coded and classified in 43 categories. Among the most frequent reasons that men indicated for being single included poor flirting skills, low self-confidence, poor looks, shyness, low effort, and bad experience from previous relationships.