For decades, Americans have argued about who may marry and what marriage actually means in legal, religious, and philosophical terms. For almost as long, two problems - the rising divorce rate and the poverty of some "divorced" children and their custodians - have fed concerns about the viability of marriage as an institution that promotes domestic stability and economic security. This Article explores the notion that domestic partnership based upon business partnership law would better serve more couples, their families, and society as a whole. It proposes a Uniform Domestic Partnership Act, loosely modeled after the UPA, as a substitute for marriage and recommends that marriage continue, without legal significance, under the exclusive control of religious institutions. By demonstrating that modern couples expect civil marriage to provide something different than couples did historically and by adapting business partnership law approaches to areas such as fiduciary duty, agency and transaction costs, and limited liability, this Article proposes a legal structure for domestic enterprises. Actually, it offers four new solutions: the Filial, the Enduring, the Caregiving, and the Provisional Domestic Partnerships.