It is normal to want to defend yourself, but when you do, it just opens it up to his responding and that is what he wants. I had to train myself to stop responding.YOU have the power, not him. There is a saying, you don't have to accept an invitation to an argument. He NEEDS you to respond ..that is the only thing he has going for himself.......getting you to engage everything he says. YOU have the power to stop this on again, off again arguing. He doesn't care what you say he is only interested in arguing with you. He is a spoiled brat acting out his frustrations....just like children do. What do we do with spoiled children throwing a tantrum? Ignore them.