Attractive alternative partners pose a relational threat to people in romantic relationships. Given that people are often limited in their time and energy, having the capacity to effortlessly respond to such relational threats is extremely useful. In 4 studies, we explored how people's identity in terms of their romantic relationship—their relationship-specific identity—affects their relationship-protective behaviors. We predicted that once a relationship becomes a part of one's sense of self, relationship maintenance responses are exhibited in a relatively fluid, spontaneous manner. In Study 1, we assessed the convergent and divergent validity of relationship-specific identification, demonstrating how it is associated with other relationship constructs. In Study 2, we found that less identified participants mentioned their relationship less than those high in relationship-specific identification, but only when interacting with an attractive member of their preferred sex. In Study 3, using a dot-probe visual cuing task, we found that when primed with an attractive member of their preferred sex, those low in relationship-specific identification gazed longer at attractive preferred-sex others compared to those high in relationship-specific identification. In Study 4, we found that relationship-specific identification was associated with relationship survival 1–3 years after the initial assessment. The present results demonstrate that relationship-specific identification predicts relatively spontaneous, pro-relationship responses in the face of relational threat.