Yes, you can file a claim for alienation of affections against the girlfried, especially if you suspect she was around before you and your husband separated. Of course, whatever evidence you can find to prove that the affair began before you and he separated is great too. But, since you are still married, even evidence of post separation marital misconduct is admissible.
When your husband files for divorce, you will have 30 days to answer the complaint. If you and he have not signed a separation agreement dividing the marital property, and dealing with alimony, you should either have that completed before the divorce is final, or file your claims for equitable distribution of the property, alimony, child custody and child support in your answer to his divorce complaint.
If you do not file claims for equitable distribution and alimony before the divorce is final, you will lose the right to those claims after the divorce is final.
Shonnese D. Stanback
The Rosen Law Firm
4101 Lake Boone Trail, Suite 200
Raleigh, North Carolina 27607
919.256.1534 direct voice
919.256.1667 direct fax
919.787.6668 main voice
919.787.6361 main fax
The response posted above is based upon the limited factual information made available and is not intended as a full and complete response to the question. The only reliable manner to obtain complete and adequate legal advice is to consult with an attorney, fully explain your situation, and allow the attorney sufficient opportunity to research the applicable law and facts required to render an accurate opinion. The basic information provided above is intended as a public service but a full discussion with an attorney should be undertaken before taking any action.