Alienation of affection and criminal conversation are potential legal claims or causes of action against a person who committed adultery with your spouse—the paramour or lover with whom your spouse had an affair. These claims are based on the idea that the person with whom your spouse cheated destroyed or alienated the love and affection in your marriage.

Alienation of affection claims are no longer recognized by courts in most states—but Hawaii, Mississippi, New Mexico, North Carolina, South Dakota, and Utah do recognize such claims. And in some states that do or do not not recognize such claims, the cheated-on spouse may seek an unequal division of the marital estate based on fault in the breakup of the marriage.

The details of alienation of affection laws (sometimes called heart-balm laws) vary from state to state among the states that do recognize such claims.

In the state of Missouri, the claims of alienation of affection and criminal conversation are not recognized by the courts. Missouri does not allow for legal action to be taken against a third party (the 'paramour' or lover) for the breakdown of marital affection due to an affair with a spouse. While some states do recognize these claims, Missouri is not one of them, and thus, these causes of action are not applicable within the state. However, when it comes to the division of the marital estate during a divorce, Missouri courts may consider marital misconduct, including adultery, when deciding on the division of property. This means that while a direct lawsuit for alienation of affection is not possible, the actions of a spouse that contributed to the end of the marriage may still influence the financial outcomes of the divorce proceedings.