R.C.S.E.

Relationship Contingent Self-Esteem – a psychological state where one’s sense of self is unhealthily reliant on a romantic relationship.

According to a detailed article in The Journal of Personality & Social Psychology [PDF] by C.R. Knee et al.:

R.C.S.E. involves more than merely having a relational identity … feeling invested in and committed to the relationship … or including the partner within the self … . Although each of these notions reflects a manner in which the self is linked to one’s romantic relationship,R.C.S.E. specifically involves having one’s self-regard hooked on the nature, process, and outcome of one’s relationship. In this way, to someone who is higher in R.C.S.E., even minor negative relationship events can become significant because of their implications for self-worth.