I believe that what you are referring to is an Alienation of Affection suit.  Those type of lawsuits are only valid in certain states at this point in time.  Most states have abolished those laws.  But the relationship has to eb the cause of the break up of the marriage.  From what you have written here it appears the marriage was broken up before you met him (he was living elsewhere).  His wife may try and say you prevented reconciliation but that is not really the basis of that type of suit. You may be named in the divorce though.  That is another issue.  Good luck.