Popular culture is rife with messages telling couples that they alone have the power to improve their relationship. But couples are embedded in a physical and social context that can also exert both subtle and direct influence. This dissertation serves to enhance our understanding of how two external forces influence marital functioning. The first two papers examine financial resources, and the second two examine social resources. The first paper describes the challenges low-income couples face, highlighting that even when asked to report about problems within their marriage, lower-income couples describe salient problems external to their marriage (i.e., finances, children). The second paper examines differences between lower and higher income couples’ marital satisfaction trajectories, indicating that, on average, lower income couples are not less satisfied in their marriages initially, nor do they decline more quickly over time. Rather, lower income couples’ marital satisfaction fluctuates more between assessments, and there are greater differences between lower-income spouses than higher-income spouses. These two studies highlight that efforts to improve lower-income couples’ relationships should address both relational and contextual stressors targeted to specific couples at specific points in time. The third paper is a theoretical and quantitative review of the literature on social networks and relationship quality and stability. Findings from the 118 peer-reviewed studies indicate that supportive and approving social networks containing high-quality relationships are associated with better and longer-lasting relationships. However, much remains to be examined with respect to the structure of couple’s networks, longitudinal associations that clarify directionality, and moderators of these processes. The final paper examines how four-year marital satisfaction trajectories and divorce rates gathered in four independent samples of newlywed couples were predicted by the shape of couple’s courtships: 1) where couples met, 2) the length of their courtship, 3) whether spouses were friends before dating, and 4) whether partners cohabited before marriage. Across all four studies, these courtship experiences did not account for divorce, initial marital satisfaction, or slopes of satisfaction. Together, these studies offer a nuanced look at how couples’ physical and social contexts can exacerbate and buffer them from relational distress, to inform theory and practice.