My son is 13 months old. In the past 7 months, my ex had seen him maybe 4 or 5 times. They don't know each other at all. My ex doesn't even call or help me out with my son. In January 07 I asked for him to sign him over, and he said no. His name is on the birth certificate, but we were never married. I live in TX so some laws are different. I'm not sure of all of my rights or his. My fiancée wants to adopt my son. How do I prove that my ex is an unfit father? He has also been to jail 4 times in 3 months! He does drugs and sells them. He doesn't care about me or my son. Help me please!

It is very hard to do, your first and main stop will be an attorney. You will have to show he is a danger to the child basically.

You cannot force him to relinquish his rights. Your only hope is, as Chuck said, to show that he's a danger to the child. What you might try is petition in Family Court for child support. You might then use that as leverage to get him to agree to allowing your husband to adopt the child. In any case you need an attorney to help you prepare for this.