Contracts between spouses that alter the basic default rules of marital property and support are subject to widely varying legal standards across the United States. As with premarital contracts, the goals of efficiency and predictability are often in tension with other policy concerns, such as the recognition that the dynamics of an intimate relationship may distort the bargaining process. Although all states require financial disclosure as a prerequisite for an enforceable marital contract, some impose additional procedural and substantive criteria beyond those applied to premarital contracts. The varying legal standards, in turn, are rooted in competing visions about the meaning of marriage. These divergent constructions of marriage range from a status defined by immutable rights and obligations to an individualized relationship subject to private ordering in almost all respects. In light of evolving social attitudes about marriage and the diminishing popularity of the institution itself, this Essay ultimately recommends a flexible framework that provides a broad scope of contractual freedom while still holding spouses to a core duty of honesty and good faith in forming marital contracts.