Although studies on romantic relationships are abundant, cumulative experiences in intimate relationship dissolution (i.e., dissolution of cohabitation and marriage) during young adulthood is not yet completely understood. Using a nationally representative sample of 9,275 young adults, we investigated heterogeneity in timing and frequency of relationship dissolution during young adulthood, as well as its developmental precursors to dissolution. Results indicated four distinct relationship-dissolution classes that ranged from those who maintained stable romantic relationships to those who experienced multiple cohabitation dissolutions and divorces from ages 18 to 30 years. Early socioeconomic adversity predicted relationship-dissolution trajectories directly and indirectly through psychosociodemographic mechanisms in adolescence, including disrupted transitions to adulthood, conflict in dating relationships, and low levels of future orientation. Our findings highlight the heterogeneous romantic relationship trajectories of young adults and support the importance of the person-centered approach in elucidating developmental pathways underlying the longitudinal transitions in romantic relationships. (PsycINFO Database Record (c) 2019 APA, all rights reserved).