How do I get my divorce if I had a child 2 yrs after me and my ex husband separated. Do i get him to do a paternity test proving he is not the father

Although a child born during the marriage is legally presumed to be the child of the parents (including the father),  if your spouse is not claiming paternity, I don't see the problem.   The real question is whether your estranged spouse is challenging paternity of the child that was born, post-separation? If he is not claiming paternity, this issue can be addressed in your Complaint for Divorce and resolved at that time. I suggest that you consult with a family lawyer in your area to discuss the proper way to address this issue in the Complaint for Divorce.  Best of luck~