One Trend, a Patchwork of Laws. An Exploration of Why Cohabitation Law is so Different throughout the Western World

Abstract Western jurisdictions have adopted remarkably diverging legal approaches to address unmarried cohabitation, ranging between contractual approaches, registered partnerships, and default regimes. This article explores to what extent the large diversity in cohabitation law is prompted by socio-demographic factors, legal tradition and family ideology. The experiences from Belgium, Sweden, England and Wales, New Zealand, and the United States suggest that cohabitation law is mostly ideologically motivated, with socio-demographic factors only having a minor impact. Diverging views on the preservation of the traditional family and the autonomy versus protection of the vulnerable partner-spectrum, in particular, seem to form the backbone of a jurisdiction’s preference for a contractual approach, a registered partnership, or a default regime. Path dependency brings an important nuance to this model. Because existing rights and benefits often prove difficult to turn back, a shift in policy generally fails to eliminate all traces of the former legal framework.