Stepfamily complexity remains largely neglected in contemporary literature despite links with marital instability. As around 50% of U.S. adults report close step-relationships, this study explored difficulties associated with stepfamily life (i.e., social and family difficulties and difficulties with roles of the spouse, parent, and stepparent) and marital stability for different stepfamily constellations (depending on which of the couple or both had previous children). This study used dyadic relationship data from 651 couples. Wives reported higher levels of parenting and stepparenting difficulties. Social and family difficulties were highest for stepmothers without biological children of their own, possibly because of unmet parental expectations. Therefore, being a stepmother without one’s own children might present unique difficulties placing stepmothers at higher risk for family-related strain.