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 Illinois, claims for alienation of affection and criminal conversation are not recognized. Illinois abolished these causes of action, which are also known as 'heart-balm' torts, with the enactment of the Illinois Marriage and Dissolution of Marriage Act. This means that a spouse in Illinois cannot sue a third party for damages on the grounds that the third party had an affair with their spouse and thereby alienated their spouse's affection. While these claims are still recognized in a few states, Illinois does not allow for such legal actions. Regarding the division of marital property, Illinois follows the principle of equitable distribution, which means that marital property is divided equitably, but not necessarily equally, in the event of a divorce. Fault in the breakup of the marriage, such as adultery, may be considered by the court when determining an equitable division of property, but it is just one of many factors that the court will consider.