Legal Question in Family Law in Texas

I'm afraid that it is not. If you were married to him at the time of birth, then he is the presumed father. A presumed father's paternity can only be rebutted by a court order or a denial of paternity filed along with an acknowledgement of paternity by the biological father.

You can file to have him declared not to be the father and, alternatively to terminate his rights, but he will have to be served with that.

The actual father would have to be terminated and that means that he also must be served and have a chance to appear. If you don't know who that is, then there are other procedures to terminate him. You need an experienced family law attorney to guide you through this process because it is full of traps and you don't want to later find out that the termination was not valid.