The one thing that jumps out at me is that your son is going to take more notice of what you do than what you actually say to him.
He's going to take more notice of how you handle moms violence than how you actually tell him he should handle it.
And he's going to watch how you take care of yourself and copy that too.
That isn't intended to minimise the verbalisation/chat/ talk/telling him what's what, he needs to hear that, but he also needs to see your example and he needs to see you stick to your beliefs/boundaries and see that they do actually work.
Show him how to do it as well at telling him.