This paper examines when relational self-expansion is especially beneficial for relationship outcomes. Relational self-expansion is most strongly associated with commitment among people with an especially strong motivation to self-expand, both cross-sectionally and longitudinally.
Hughes, E. K., Slotter, E. B., & Emery, L. F. (in press). Expanding me, loving us: Self-expansion preferences, experiences, and romantic relationship commitment. Self and Identity.