In a super-aging society like Hong Kong, a huge number of older couples are getting frail together. Current research on informal carer dominantly takes a spousal caregiving perspective by clearly distinguish between roles of caregivers and care-receivers, overlooking a prevalent phenomenon that both spouses are at risk of functional decline and help with each other in daily life. Despite there is a few literature on the concordant health outcomes between spouses, no systematic research has been conducted to examine couple’s experiences of handling daily stressors and its well-being impacts. To address these research gasps, the proposed study advocates a paradigm shift from an individual-based examination of caregiver and care-receiver to investigating collaborative care arrangements within older couples and takes a first step to investigate the vivid experiences of how functionally impaired couples dealing with daily stressors. Objectives: The study aimed to test specific functions of couple’s collaborative dynamics in mastering daily stressors that could facilitate more positive individual and relational well-being outcomes, and whether the effectiveness of collaboration varies as a function of perceived control of self and spouse during collaboration. By integrating interdependence theory and frameworks of dyadic coping, this study will test two sets of hypothesizes: (1) spousal collaboration buffers the temporal relationship between daily stressors and psychophysiological responses, and such buffering effects are enhanced when spouses exhibit a reciprocal pattern of control in collaboration; and (2) more frequent use of collaboration to deal with daily stressors is prospectively associated with greater well-being and marital satisfaction. Methodology: We propose to use a combined research design comprising a longitudinal survey and ecological momentary assessment (EMA). The EMA research protocol has been validated in our previous work as a feasible and reliable method for studying real-life experiences of community-dwelling older adults. A sample of 75 older couples wherein both spouses reported functional decline will be recruited to participate in a baseline survey, a 14-day EMA, and a 12-month follow up survey. During the 14-day EMA period, each participant will be instructed to use mobile devices to provide self-report data (e.g., daily stressors, affect) and cardiovascular recordings four times daily. Conclusion: The findings of this study will serve as the first evidence of the phenomenon of collaborative dynamics of functionally impaired couples’ mastering on daily problems. Findings will also inform the development of couple-centered care models that address the joint health needs of both spouses in super-aging societies globally.