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 Maryland, marital property is not recognized as community property, as Maryland is an equitable distribution state rather than a community property state. This means that during a divorce, marital property is divided in a way that is equitable, but not necessarily equal. A marital property partition agreement, known in Maryland as a Marital Settlement Agreement or a Postnuptial Agreement, is a legal document where spouses can agree on how to divide their property in the event of a divorce. Such agreements can include the division of both assets and debts and must be in writing, voluntary, and notarized to be enforceable. The agreement allows spouses to convert marital property into separate property of one spouse, thereby altering the default rules of equitable distribution. If spouses cannot agree, the court will divide the property. It's important to note that such agreements are subject to certain legal standards and can be challenged in court if they are deemed unconscionable or if there was a lack of full disclosure, duress, or coercion. An attorney can provide guidance on drafting a valid postnuptial agreement in Maryland.