“…Although longitudinal studies can provide answers to questions of directionality between relationship and sexual satisfaction, such studies are few and results have been inconsistent. There is mixed evidence for any directional effect (i.e., Byers, 2005), with some researchers finding evidence for contradictory unidirectional effects (i.e., Cao, Zhou, Fine, Li, & Fang, 2018; Fallis, Rehman, Woody, & Purdon, 2016; Henderson-King & Veroff, 1994; Sprecher, 2002; Vowels & Mark, 2018; Yeh, Lorenz, Wickrama, Conger, & Elder, 2006) and some have identified preliminary evidence for a bidirectional relationship (McNulty et al, 2016). McNulty et al (2016) tested a bidirectional model and found both that earlier levels of relationship satisfaction predicted later levels of sexual satisfaction and that earlier levels of sexual satisfaction predicted later levels of relationship satisfaction in a sample of new marriages.…”