Can family policy affect well-being of individuals without altering the resources available to their families? This article examines the extension of alimony rights and obligations to cohabiting couples in Brazil. For women in intact relationships, alimony rights upon dissolution should improve outside options, strengthening their negotiating positions, and increasing their influence over intrahousehold allocation of resources. Robust econometric evidence indicates that more decision power in the hands of women impacts hours worked by female adults and investments in the education of children. This suggests that family policy and models of family decision making should take intrahousehold heterogeneity of preferences into account. © 2006 The Authors. Journal compilation © Royal Economic Society 2006.