If you have suffered unreasonable harshness and "discipline" in your life, it is easy to think there is nothing between doormat and attacker, that any sort of control you put on your child will harm them and distress them. The opposite is true, we need to do them the honour of teaching them boundaries and control.I desperately want to lash out but I can't, he's little and doesn't understand.
If there are no limits, a child HAS to go on pushing until they find them, and as they get older they push further and harder. So you would be helping both of you if you said, in a calm voice, "You are not allowed to hit Mummy. If you do it again you will have to sit on the naughty chair" and then do it as soon as it happens. My children are grown up, and say they were afraid of that chair, but never of me. We have a good, open, loving, relationship.