Marital Misconduct Missouri

General Summary: In Missouri, it is the policy of the courts to promote amicable settlement of disputes between parties to a marriage attendant upon their separation or the dissolution of their marriage. The parties may enter into a written separation agreement containing provisions for disposition of any property owned by either of them, maintenance of either of them, and support, parenting, and parental contact with their children.

In a subsequent proceeding for dissolution of marriage or for legal separation, the terms of the separation agreement, except those providing for the support, parenting, and parental contact with children, are binding upon the court unless it finds, after considering the economic circumstances of the parties and any other relevant evidence produced by the parties, on their own motion or on request of the court, that the separation agreement is unconscionable.

Statutes:
Missouri Revised Statutes
Chapter 452
Dissolution of Marriage, Divorce, Alimony and Separate Maintenance

Separation agreements authorized, effect of--orders for disposition of property, when--terms of agreement, how enforced:
1. To promote the amicable settlement of disputes between the parties to a marriage attendant upon their separation or the dissolution of their marriage, the parties may enter into a written separation agreement containing provisions for the maintenance of either of them, the disposition of any property owned by either of them, and the custody, support and visitation of their children.
2. In a proceeding for dissolution of marriage or for legal separation, the terms of the separation agreement, except terms providing for the custody, support, and visitation of children, are binding upon the court unless it finds, after considering the economic circumstances of the parties and any other relevant evidence produced by the parties, on their own motion or on request of the court, that the separation agreement is unconscionable.
3. If the court finds the separation agreement unconscionable, the court may request the parties to submit a revised separation agreement or the court may make orders for the disposition of property, support, and maintenance in accordance with the provisions of sections 452.330, 452.335 and 452.340.
4. If the court finds that the separation agreement is not unconscionable as to support, maintenance, and property:
(1) Unless the separation agreement provides to the contrary, its terms shall be set forth in the decree of dissolution or legal separation and the parties shall be ordered to perform them; or
(2) If the separation agreement provides that its terms shall not be set forth in the decree, only those terms concerning child support, custody and visitation shall be set forth in the decree, and the decree shall state that the court has found the remaining terms not unconscionable.
5. Terms of the agreement set forth in the decree are enforceable by all remedies available for the enforcement of a judgment, and the court may punish any party who willfully violates its decree to the same extent as is provided by law for contempt of the court in any other suit or proceeding cognizable by the court.
6. Except for terms concerning the support, custody or visitation of children, the decree may expressly preclude or limit modification of terms set forth in the decree if the separation agreement so provides. Section 452.325

Case Law:

A husband and wife, in contemplation of a dissolution, may validly contract between themselves regarding the settlement of property rights emanating from the marital
relationship. Muhlhauser v. Muhlhauser, 754 S.W.2d 2, 4[2] (Mo.App. 1988)

The normal rules of contract construction apply to marital settlement agreements. The cardinal rule in the interpretation of a contract is to determine the intention of the parties and to give effect to that intention. Where there is no ambiguity in the contract the intention of the parties is to be determined from the contract alone. Where a contract is not clear it is construed as it is understood and acted upon by the parties.
Griffin Contracting Co., Inc. v. Hawkeye-Security Ins. Co., 867 S.W.2d 602, 604 (Mo.App. 1993)