Has he actually said he wants to be in the child's life? In my experience there is a world of difference between someone who doesn't want a relationship with their child and soneone who does. I learned the hard way that you can never force someone to be in your child's life and its more damaging to the child to do that. I was in an extremely rocky, on/off relationship with my sons father for years until we eventually broke up when son was 4. He didn't maintain regular contact and, at 10 years old, no now longer sees him through choice, because his dad doesn't know who he is, what his interests are etc. I think I tried so hard with his dad and stayed through a lot of shit I should never have put up with because I knew deep down if we broke up, he wouldn't continue his relationship with our son. And it took me a LONG time to realise that this isn't my fault. He doesn't have a relationship with his son because he made the choice not to. It was nothing to do with me and I've finally learned to not blame myself for that.
I'm pregnant now again with my fiance and I can tell you, that even if we split up, if I moved away 100 miles, nothing would stop this man being in this child's life. Because, again, that's HIS choice.
Ultimately, whether he will be involved is up to him. You can leave the door open for him, maybe in a few years he'll grow up and become a decent person. You need to go easy on yourself and understand that whatever he chooses to do, won't stop you raising a wonderful child. Having been a single parent for several years, but 10 year old son in my proudest achievement in life. I did well, and I did it alone.
I will leave you with a last piece of advice which I wish someone had given me 10 years ago... Please look into what the consequences are if you decide to put him on the birth certificate. Not many people realise how much power absent parents have once their name is on it. And it's nigh impossible to remove them but you can always add them at a later date. It will seem ages in the future but for example, my sons birth father could pop up tomorrow and contest the secondary school I've chosen for him, despite mow longer being in his life, all because his name is on that bit of paper.
Good lucks and trust your instincts xx