The paper finds that because people in lower-SES contexts experience more precarious environments, they are more concerned about self-protection in their relationships than are those in higher-SES contexts, and they also think about their relationships in more self-protective ways. However, the links between social class and self-protection only emerge when people in lower-SES contexts feel vulnerable in their relationships.
Emery, L. F., & Finkel, E. J. (in press). Connect or protect? Social class and self-protection in romantic relationships. Journal of Personality and Social Psychology.