Is it the right thing to do???

So my ex and I ended up breaking up when I was like 3-4 months pregnant. It wasn't going well and he just really changed into someone I couldn't be in a relationship with he literally said my happiness doesn't matter. Now we didn't stop talking I still stayed connected with him since he is the father. He got upset randomly from old things that happened when we were to together and for some reason he wanted to take it out on my mother, who has been my main support he hasn't done anything but stress me out and complain about irrelevant things. Anyways, I told him I wasn't going to let cuss my mother out or be disrespectful to her and he said he's done talking to me and will contact me when he cares to talk to me. True to his word he hasn't and now I have everything this baby will need without him chipping in a penny. Is it wrong for me to just decide even if he does contact me to not respond? I don't feel like I can depend on him for anything but to cause drama and stress in my life and I want to be at my best for my baby. I don't want to have to be so wrapped up in all his trouble while taking care of a newborn and getting a job. I just feel like he's too all about himself he wants things to go his way and everything is just my fault and has always been my fault. I don't want to contact him evert really I feel like he'll just be a negative force on my baby and me. Should I reconsider and start talking to him when he decides to talk to me or should I just keep him out until I'm ready to deal with him? Or what should I do period.