I'm going to tell my boyfriend to stop talking to his lying, cheating ex when he insists it's because of their child.
Are you sure he's talking to her because of their child?
My boyfriend confessed it to me himself.
I understand why you would be bother by your boyfriend talking to his ex, but you can't control who someone talks to. Your boyfriend is free to talk to whoever he wants, and that includes his ex. As you said, he has a kid with her so you shouldn't force him to stop seeing his child.
I'm going to try to stop him any way I can. I'm pissed in the way this relationship is going.
You should talk to him about how you feel about him talking to his ex instead of forbidding him; that sounds really controlling. Maybe there's a way he can see his kid without seeing her, because parents should be able to see their kids.