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 Oklahoma, which is an equitable distribution state rather than a community property state, marital property is not automatically considered to be owned jointly by both spouses. Instead, property acquired during the marriage is divided equitably, though not necessarily equally, in the event of a divorce. A marital property partition agreement, known in Oklahoma as a postnuptial agreement, allows spouses to agree on how their property should be classified as separate or marital and how it should be divided in the event of a divorce. These agreements must be in writing and are subject to certain legal requirements to be enforceable, such as full disclosure of assets and voluntary signing without duress or undue influence. Oklahoma statutes do not specifically address marital property partition agreements, but they are recognized under general contract principles and family law precedents. If spouses cannot agree on the division of property, the courts will intervene and divide the property in an equitable manner, considering factors such as the length of the marriage, contributions to marital assets, and the economic circumstances of each spouse.