When he begins his bad behaviour, is it possible you could physically turn away and immediately become involved in something else that he would be able to see is more interesting for you than engaging with his behaviour? Since he wants to dominate, as you say, then he would be incapable of that every time he starts acting like a spoiled brat. Also, could you think of him as a spoiled brat, and show that in your body language, instead of thinking of him as a monster he apparently is, to reduce his dominance over you?

Just thoughts. Maybe helpful, maybe not. Trying to be helpful.