Sounds like you know what to do.

“I don’t know if I should really distance myself again to work on myself and strive for something better or if I should just keep up the communication in a friendly way and try to get over it the hard way.”

Actually, you do know. Because one of those is not really an option, is it? You can’t get over this tangled emotional mess if you’re constantly talking to him. He’s the father of your child, and some communication may be inevitable, but to be honest he doesn’t sound mature enough to be a parent. And the stuff he said to you while you were pregnant was horrible, by the way!

I think you need some distance here. You need to focus on yourself and your boy, on building a good life for the two of you and making room for someone who is ready to be a father to him and a partner to you. Wish you all the best.