This study began with an interest in how long-term marital couples are able to maintain stability in light of changing social and personal contexts. Using a qualitative grounded theory method as a part of an ongoing study of how couples manage the tension between ideals of partnership and stability over time, 21 couples were selected by theoretical sampling. Participants had to be living together for at least 10 years, with an oldest child at least aged 6. Flexibility—a dyadic process involving how partners adjust to and are influenced by each other, situations, environments, and life changes—emerged as a key component enabling couples to maintain marital stability. This analysis focuses on three processes that seem to influence couples’ ability to maintain flexibility in their relationships: (a) mutual decision making, (b) mutual accommodation regarding household tasks, and (c) mutual giving of personal time. Demonstrating these was associated with a focus on the relationship.