Borderline personality disorder (BPD) is associated with romantic relationship distress and dissolution. The complex interaction between BPD and romantic relationships warrants further attention. Dyadic interviews (N = 10) were conducted to examine the experience and impact of BPD on couples’ relationships. The results of interpretative phenomenological analysis consisted of two superordinate themes describing the couple experience of navigating BPD: (a) the shared experience of BPD as a relational stressor; and (b) adaptive dyadic coping in the context of BPD. Although BPD was experienced as a relational stressor, dyadic coping and shared externalization of BPD emerged as central components to adaptive couple functioning. Most couples reported that therapy was a critical external resource in their journey toward adaptively functioning in the context of BPD, both intrapersonally and interpersonally. The lived experiences of these couples provides therapists with an increased understanding of the resources that support adaptive dyadic coping with BPD.