This chapter focuses on the theoretical basis behind intergenerational attachment styles and how they present in romantic relationships. In this chapter, we review the conceptual literature on attachment styles, their development and maintenance across the lifespan. We also explore the role of mutual emotional regulation in disrupting relational distress and improving relationship functioning. We proceed to synthesise efficacy studies and evidence-based research on relational interventions with couples, most commonly presenting concerns in couples therapy and the role of couples therapy in improving romantic relationships across cultural contexts, gender and sexuality identifications. We summarise what has worked, with whom and why while reviewing the various measures and types of clinical interventions offered to couples and report on change scores in outcomes of attachment avoidance/anxiety, relational conflict, relationship functioning and partner satisfaction. Finally, the book chapter presents three case studies with South-Asian couples across diverse life stages, relationship statuses, gender identities and sexual orientations using attachment-based and emotion-focused interventions.