Legal advice.. Step parent adoption.

My husband wants to adopt my son. He has been the father figure my child has only known. I was married to his biological father for 18 months, but we had separated 4 months into his marriage, a week after I found out I was pregnant. He was abusive when we we're together and I finally made him leave. I also found out that he had gotten a young girl pregnant (he was 21, she was around 15) when he attempted to come back. Anyways, it took me 18 months, and the courage of my (now) husband to finally divorce him. We've been divorced now for 9 months on the 5th of may. He has never seen or met my son. He didn't know the date of birth, the gender, or his name until I finally was able to get contact with him to tell him I wanted a divorce. (None of which I withheld, but I didn't know how to get a hold of him, and never tried to contact me) when we got divorced I was told,that he would have to go 18 months without any contact for my husband to file for a step-parent adoption. My sons almost 2, and I don't know if I can count the fact that his biological dad hasn't had any kind of contact with him in his almost 2 years of life. Or if it has to go from the divorce. In child support he has only paid a total of $368 dollars and it wasnr consecutive payments.

I'm kind of lost on what to do. Has anyone else done this, or been through it?

My husband is military. The divorce took place in Arkansas, but we are now in Texas, if that helps any.