Sexual well-being is an important contributor to romantic relationship quality, health, and quality of life, yet couples face significant disruptions to their sexuality during the transition to parenthood. While there is evidence of variability in the sexual well-being of new parents, distinct classes of dyadic trajectories have not been established. Sexual frequency, desire, satisfaction, and distress are each unique components of sexual well-being and may follow different patterns of change within couples. We sought to establish classes of trajectories of four aspects of sexual well-being for couples in the transition to parenthood as well as the associations among identified classes. Couples (N = 203) expecting their first child completed online standardized measures of sexual well-being at 20 and 32 weeks in pregnancy and at 3, 6, 9, and 12 months postpartum. Dyadic latent class growth analyses were conducted to identify classes of trajectories for each facet of sexual well-being, and dual trajectory analyses examined the probability of group membership across classes. Couples' sexual well-being over time was heterogeneous. Sexual frequency had two classes: high (33%) and low (67%); sexual desire had three classes: moderate (36%), high (25%), and discrepant (39%); sexual satisfaction had two classes: high (64%) and low (36%); and sexual distress had two classes: low (76%) and discrepant (24%). Overlap in classes of sexual well-being was variable such that high and low or discrepant (between partners) classes did not always co-occur. Findings provide more nuanced information about new parents' postpartum sexual health, which may facilitate early assessment and intervention. (PsycInfo Database Record (c) 2021 APA, all rights reserved).