My husband has a child with his ex who has been married since she was 18 but they have not been together in years. Does he have to pay child support?

  The law says that if a woman is married at the time of conception or birth, the husband is the presumptie legal father of the child. He would stay as such unless he or the "wife" filed for a disestablishment of paternity.     On the other hand, did your husband sign the birth certificate?  If he did there is a presumption of paternity.      That said, if a petition is filed to establish child support against your husband, he would need to bring up this up- the mother's fraud on the birth certificate, that she was married, etc.  Because this is a bit unusual, if he does receive a summons it would be worthwhile to speak with an attorney.   Best of luck, Cindy S. Vova Law Offices of Cindy S. Vova  Broward/Palm Beach 954-316-4596/561-962-2785