The Chilean legislation on stable non-marital partnerships presents a contractual system of rigid nature, resembling marriage, but far from cohabitation. This research seeks to analyze the Civil Union Agreement and to study its effectiveness to fulfill the legislative objectives that were established upon its creation. To that end, an eminently conceptual analysis is carried out throughout the legislative history of the civil union, its social reception, and its contractual effects. These aspects evidence an individualistic model that restricts the autonomy of the couple and concentrates on the economic facet of the family. As a solution, this study proposes the abandonment of this exclusively patrimonial approach and the adoption of cohabitation as part of the regulation of civil unions.