Successful mate poaching is a form of infidelity that occurs when one partner knowingly attracts the mate of another with the intention of starting a sexual and/or romantic relationship with this individual. Relationships formed from poaching tend to be of lower quality than their non-poached counterparts. A history of poaching might reflect a sociosexuality that propels seeking new partnerships without regard for exclusivity. It is unknown whether serial poaching for relationship formation is linked to more permissive sociosexual orientation. Adults (N = 653; aged 25-40; 57% women) in a romantic relationship completed online surveys assessing mate poaching, poaching history, sociosexuality, and relationship quality (commitment, satisfaction, trust, jealousy). Those in a poached relationship at the time of the study had a more extensive history of poached relationships and a more permissive sociosexuality. Participants who reported a more extensive history of mate poaching reported poorer quality relationships. The link between poaching history and relationship quality was partially accounted for by sociosexuality. This research adds to our understanding of difficulties that may be associated with the relationships of individuals who use poaching as a relationship initiation strategy, and the challenges that permissive sociosexuality may present for maintaining long-term relationships.