Understanding ways to strengthen marriage in middle age and beyond is increasingly important as the population of older adults rises. Using couple-level growth curve modeling in a sample of 371 middle-aged husbands and wives in long-term, enduring relationships, we examined the association between "joint activities," an index of couple connectedness, and "couple religiosity," an index focused on active participation in organized religious activities, across a 10-year period, using data from the years of 1991, 1992, 1994, and 2001. Confirming expectations there was a bidirectional and positive relationship between couples' religiosity and joint activities. Follow-up analyses indicated that greater religiosity at baseline or greater levels of joint activities at baseline produced particularly strong cross-lagged effects when the other construct was initially low, suggesting that these constructs are mutually protective in long-term marital dyads and become more tightly connected across later middle age. Exploratory comparisons of separate models for husbands and wives indicated that effects were stronger among wives.