in my marriage i had a child with someone else other than my husband and the other man is now demanding rights can he get any and which ones?
He can get whatever "rights" the Judge will give him.
He can ask for an order that states that he's the legal father of the child; he can ask for custody (he won't get it); he can ask for access via a visitation order (which he'll get); and he'll probably be ordered to pay child support.
All of this assumes that he is in fact the biological father. You have the right to demand DNA testing.