A marital property partition agreement—also known as a partition and exchange agreement, a postmarital agreement, or a postnuptial agreement—is an agreement between spouses during marriage to convert marital property (also known as community property in some states) to one spouse’s separate property.

Property that is jointly owned by spouses or domestic partners (often owned as joint tenants with a right of survivorship) may also be partitioned or divided in a lawsuit or court action rather than by agreement of the spouses.

Laws regarding marital property partition agreements vary from state to state and are generally located in a state’s statutes—often in the family code or domestic relations code.

In Wyoming, marital property is not classified as community property since Wyoming is not a community property state; instead, it follows the common law system of equitable distribution. A marital property partition agreement, also known as a postnuptial agreement in Wyoming, allows married spouses to agree on how their marital property should be divided in the event of a divorce or death. Such agreements must be in writing and are subject to certain legal requirements to be enforceable, including full disclosure of assets and liabilities, and both parties must enter into the agreement voluntarily and without coercion. The agreement can include provisions for the division of property, debt responsibility, and other financial matters. If spouses decide to partition or divide jointly owned property without an agreement, they would typically need to file a lawsuit for partition, and the court would divide the property equitably. Wyoming statutes pertaining to postnuptial agreements and the division of property in a divorce can be found in the Wyoming Statutes, particularly within the sections dealing with domestic relations.