It's pretty clear that he's interrupting your conversations about your shared child to try to keep emotionally abusing you. Just live in Reality II, not Reality I (The Verbally Abusive Relationship by Patricia Evans -- a fantastic book I'm reading right now; have you read it yet?) and interrupt him EVERY TIME he tries to derail that conversation back to himself. If you interrupt him consistently, even if you sound repetitive, he'll see that you won't put up with his abusive behavior anymore. If you have full custody of your child together, write down every phone call or visit where he behaves this way, in case you need to go in front of a judge again. Record the conversations on your phone (there's an app that does it) if you have to, to play for the judge.

Cover your bases. That's what you have to do.