• adult attachment;
  • caregiving;
  • close relationships;
  • stress

In this commentary, we discuss the significant role that relationship partners assume in the everyday lives of individuals. As Shaver and Mikulincer's excellent review indicates, the partner seems to be missing from large sections of attachment theory and research. This is problematic because partners are often the most salient and important feature in an individual's daily environment. We discuss why partners are “missing,” why their inclusion in research is essential, and how bringing the partner more directly into attachment theory and research will provide novel and important insights into romantic relationships. We highlight these points by discussing research that has examined the impact of partners on relationships in the context of Simpson and Rholes's (2012) attachment diathesis-stress process model.