Faced with ageing populations and increasing longevity, many OECD countries are reforming their pension, healthcare, and long-term care systems. Understanding the joint survivorship of spouses is of particular importance for determining the liabilities of public and private pension providers, for retirement and financial planning, and for the design of social welfare programmes, such as survivor benefits, healthcare subsidies, LTC policies, and housing support for ageing couples, for labour supply projections, budgetary estimations, and demographic analyses. This paper investigates the joint life expectancy of heterosexual couples at retirement ages in Spain. We use a coherent functional demographic model to produce age-specific mortality rate forecasts for men and women and compute estimates of period, cohort, and gap joint life expectancy, disaggregated by age and sex. The findings show that estimates of joint life expectancy at the age of 65 are nearly 1.5 years higher using a cohort approach compared to that obtained using a classical period approach. The results show that in couples with a significant age gap, particularly when the younger partner is a woman (common in many cultures), joint life expectancy dynamics results in longer widowhood periods. This ultimately affects survivor pension entitlements, can lead to imbalanced caregiving responsibilities, influence lifestyle choices, stress levels, and shared quality of life, demanding more financial resources, emotional resilience, and social support for the surviving partner.

This work was supported by national funds through FCT (Fundação para a Ciência e a Tecnologia), under the project - UID/04152/2025 - Centro de Investigação em Gestão de Informação (MagIC)/NOVA IMS - https://doi.org/10.54499/UID/04152/2025 (2025-01-01/2028