This article examines the impact of self-expansion, a person’s motivation to grow their self-concept, on romantic relationships. Previous research has highlighted self-expansion’s role in relationship building and maintenance areas such as attraction, commitment, and satisfaction. We explore the nature of self-expanding activities and the impact of integrating them into relationships – greater satisfaction, commitment. We also look at the consequences of insufficient self-expansion – lack of commitment, interest in alternative partners, and infidelity. All of which culminates in the understanding that self-expansion is an important component in romantic relationships in all stages from relationship building, to nurturing, and maintaining.