Cohabitation and Marriage: Complexity and Diversity in Union‐Formation Patterns

Abstract Nonmarital cohabitation and marriage are now fundamentally linked, a fact that is routinely reflected in current research on union formation. Unprecedented changes in the timing, duration, and sequencing of intimate co‐residential relationships have made the study of traditional marriage far more complex today than in the past. It is now clear that a white, middle‐class, American‐centric research template has become increasingly anachronistic. In this review article, we begin by providing an overview of contemporary theory, empirical approaches, and demographic trends in cohabitation and marriage, focusing primarily on the United States, but also distinguishing the U.S. from patterns found in other high‐income societies, including European countries, Canada, Australia, and in East Asia. We place the spotlight on the causes and consequences of union transitions. We identify the commonalities between cohabitation and marriage, but also key differences that are expressed unevenly across different populations and cultural groups. The rise in nonmarital cohabitation has upended conventional theoretical models and measurement approaches to the study of traditional marriage, complicating matters but also reinvigorating family scholarship on union formation and its implications for partners, children, and society.