There are two potential claims which can be made under North Carolina Law, depending upon the facts. First, Alienation of Affection, which would require the plaintiff to establish:
1. A marriage which entailed love between the spouses in some degree;
2. That the spousal love was alienated and destroyed; and
3. That the defendant's malicious conduct contributed to or caused the loss of affection.
Another possibilty is "criminal conversation" which requires that the plaintiff establish, subject to a three year statute of limitations:
1. An act of intercourse between the plaintiff's spouse and the other person; and
2. The existence of a valid marriage between the the plaintiff and your adulterous spouse.
Given that you apparently remain married, a "criminal conversation" action would seem more viable. I am not sure what you might be able to recover in damages. If you are serious about pursuing this, consult a lawyer.