Encouragement or advice please..

I'm so scared for my baby boy.. His dad and I broke up on really bad terms, then I found out I was expecting.. I have barely saw or talked to him in the four months that I've been pregnant.. When we talk he doesn't want to talk about the baby he wants to talk about me when I bring up the baby I get hung up on.. And I can't be with him because he's a cheater and just not a good person period, all he does is cause me stress and disappointment. But he's the father of my baby, and I know him and I know when I have my son he's going to try to make half ass attempts to be around. That's how he is with his 5 year old boy that he has now from a previous relationship. A half ass parent. And I'm not the kind of person to deny him a place in his child's life, but I don't want my baby to ever feel disappointed when his dad doesn't show up when he says he will or doesn't call because he's mad at me... He's been nothing but a disappointment this whole time and I know he's not going to be any better for his son than he has ever been for me. It just makes me so sad because I love my baby so much and want the best for him always but I'm afraid his dad is going to hinder that. I need him to be a great father or not one at all. My son needs that too, but I know him and I know he's only ever going to be a sorry ass dad. My baby deserves so much better.. I am really just venting, please no rude comments. If you have advice or ever dealt with this I'd like to hear from you.. thanks for reading this book, if you took the time to.