wikipedia

Alienation of affections is a common law tort, abolished in many jurisdictions. Where it still exists, an action is brought by a spouse against a third party alleged to be responsible for damaging the marriage, most often resulting in divorce. The defendant in an alienation of affections suit is typically an adulterous spouse's lover, although family members, counselors, and therapists or clergy members who have advised a spouse to seek divorce have also been sued for alienation of affections.[1]

The tort of alienation of affections often overlaps with another "heart balm" tort: criminal conversation. Alienation of affections has most in common with the tort of tortious interference, where a third party can be held liable for interfering with the contractual relationship between two parties.