Feeling understood, validated, and cared for by others, and especially by intimate relationship partners, is crucial for people’s subjective well-being, their health, and even their longevity. In contrast, misunderstandings and feelings of neglect and invalidation within the relationship are prevalent in many (therapy-seeking) couples contending with serious relationship distress. Effective relationship interventions require a precise understanding of how individuals come to believe that their partner attends to and supports oneself (called perceived partner responsiveness, or PPR), and thus the mechanisms that are central to improved intimate relationships. In this project, we will investigate emotion dynamics between partners as mechanisms underlying PPR, and leverage these processes to scaffold evidence-based interventions. Specifically, we will focus on a better understanding of emotional expression, empathic accuracy or actual empathic understanding, and their interplay; and how these constructs give rise to PPR or its absence, in healthy and clinically distressed couples respectively. This knowledge will then inform the development of an intervention aimed at improving PPR by targeting these dynamics with psycho-education and mobile technology methods. To this end, three work packages have been designed, including existing as well as new experience sampling methodology and laboratory observation studies with couples.