Not a Dom or a male, but I feel that you have every right to have him wear a condom. Just because you are submitting does not mean that it's not your body. You need to make sure that you are taking care of yourself and protecting yourself. If that's what you feel comfortable with then by all means ask him. If he's going to refuse and not respect you in this very important instance then I don't see why he would be worth dealing with at all.