Wahring et al. demonstrate that men depend more on romantic relationships than women, contradicting conventional wisdom. The Tie-Up Theory explains this through fundamental asymmetries in bonding systems: men’s receptive emotional area channels emotional needs primarily toward romantic partners, while women’s active emotional area enables spontaneous emotional connections across multiple relationships. This biobehavioral architecture, not mere socialization, explains men’s greater relationship striving, health benefits from partnership, reluctance to initiate breakups, and severe post-dissolution suffering.