Growing evidence implicates stress as a reliable correlate of relationship satisfaction; yet, existing models fail to address why some relationships are more vulnerable than others to this effect. We draw from the literature on individual differences in self-regulation to predict that individuals who are more action oriented when confronted with aversive demands will buffer themselves and their partners against the detrimental effect of external stress. Using actor–partner interdependence modeling on self-report data from 368 couples, we show that the relationship satisfaction of highly stressed but action-oriented individuals and their partners is compromised less by external stress than that of state-oriented individuals and their partners. These results held after controlling for symptoms of depression and were not moderated by gender or by age, despite sampling couples varying widely in relationship duration. Results support the view that individual differences in self-regulation, and action orientation in particular, might benefit relationships confronted by stress, thus clarifying how dyads might be affected by demands outside their relationship.