Romantic relationships are closely linked to mental and physical health. On the one hand, they can have a stress buffering effect through social support or directly through touch. On the other hand, a poor relationship quality has a negative effect and can serve as a chronic stressor. In this context, psychoendocrine substances and neurotransmitters, such as oxytocin, dopamine or serotonin play a mediating role, e.g. through the activation of reward circuits, the involvement of which has already been demonstrated in several studies. As a result, self-reporting measures in evaluative interventional and treatment studies are increasingly supplemented by psychobiological markers, such as salivary cortisol. From a clinical point of view, the inclusion of the partner is not only beneficial for the course of the disease of an individual, it also strengthens the ability to positively interact and can increase relationship quality, and health behavior. Involving the partner can also have a relieving effect for the partner and is therefore highly recommended.