Increasing numbers of older adults require help with personal or practical tasks because of disease, disability or age related health limitations. Commonly it is their partner who fulfils some, or all, of this caring role. Taking on this type of caring role is associated with poorer psychological health and changes in personal relationships. What remains unclear is the nature by which personal relationships with the care recipient, other family members, and friends change when older adults take on a caring role for their partner, and how this links to health. A mixed methods approach was used to explore changes in personal relationships and health for partner caregivers in later life. Seven older partner caregivers were interviewed about their experiences of caring for their partner, focusing on changes they experienced in their health and personal relationships when taking on the role. Waves 1 to 5 from ELSA were used to explore associations, both at one time point and changes over time, between health outcomes and personal relationship types, for older adults moving into the partner caregiver role. Synthesising the results suggest that connections between transitions in health and personal relationships, for older adults moving into a partner caregiver role, differ for different relationships. Relationships with partners and friends before becoming a partner caregiver were found to be most associated with change in health and quality of life when moving into this role. Relationships with children and family appeared to be more stable during the transitioning into the caregiver role, while partner relationships were more likely to suffer, and friendships seemed to experience most change. Positive associations found between different personal relationship types suggest a subset of particularly vulnerable partner caregivers who are in difficult partner relationships and have little support available to them from family or friends.