I need some opinions

My ex has no sort of custody arrangement what so ever. He won't come to terms on things such as child support, visitation, guidelines, etc. he just drifts around as he pleases. I keep telling him that won't work. I'm at the point where I can either let the state outline these things for him or I can fight to strip him of his rights. I haven't wanted to do that but it might be what's needed. He makes really rash poor decisions and I'm having to weigh out if it is better for my son to have his dad in his life or not. My ex started abusing drugs when I was pregnant with my son. He became a needle user. If I though for a second he was doing that still, I would definitely take his rights. I can say he did get clean and I have no reason to think he's shooting up still. He replaced that habit with drinking but he doesn't drink around my son. My best friend's child's father is room mates with him so I am fortunate to have a responsible adult keeping me informed. My ex did not get my son for the past two months until the week of Christmas. I have been informed this is due to my ex moving in a girl into his home. I don't know if I should be angry or not. I know it's his life and I have mine but I know nothing about what kind of girl is around my son. If my ex didn't have the past history he has, I wouldn't feel the need to worry like I do. I can't trust him and his choices and I'm scared my son will pay for a bad decision his dad makes.