I'm glad to read you don't have children. Please, please do not force a helpless child to have to live with this man. You have choices but a child would not.
He managed to control himself while you were pregnant. Well, hooray for him. You say this proves he can control himself and seem to be using that as some sort of proof that he will control himself.
You know what it also says? That he CAN control himself and therefore his aggressive and abusive behaviour towards you is a choice. He is choosing to be abusive towards you.
Would you ever treat someone you love the way he treats you? Do his actions show you he loves you?
You talk about loving who he is when he isn't being abusive but he isn't two people, one nice and one who treats you like shit on his shoe. There is only him. Take one part of him and you have to take all of him.
The absence of abuse isn't 'niceness'. You only think it is because it's a blessed relief to have some time where you aren't being subjected to his hatred of you.
It's also dependant on you being a good little girl pleasing your master. Step out of line and you get punished.
Is this really the life you want? There is no way he will change. They don't.
You have every right to stay and be abused if you feel that is the option you prefer, you're an adult and you can make that choice. But you don't have the right to force this life a child who won't have the luxury of choice.
I really really hope you choose to leave him. You deserve a happy life, not a cycle of abuse, relief at absence of abuse, more abuse.
I do wish you good luck, whatever your decision. I hope you choose to leave though, I truly do.