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 Connecticut, which is not a community property state but rather an equitable distribution state, marital property is not automatically divided equally upon divorce. Instead, the courts aim to divide property in a way that is fair and equitable, considering various factors. A marital property partition agreement, known in Connecticut as a postnuptial agreement, allows spouses to agree on how their property should be classified and divided during the marriage or in the event of a divorce. Such agreements must be in writing and are subject to certain legal requirements to be enforceable, including full disclosure and fairness at the time of execution. If spouses do not have a partition agreement and cannot agree on the division of property, the court will decide the division based on equitable distribution principles. It's important to note that while spouses can agree to partition or divide property, such agreements are subject to legal scrutiny and must comply with Connecticut's laws and public policy. An attorney can provide specific guidance on drafting and executing a valid postnuptial agreement in Connecticut.