Love, they are all lovely... to begin with.
Gradually over time that really, really lovely slips to lovely,
then lovely every so often,
then sometimes,
then I still remember when he was lovely,
then I can't even think straight for worrying what I've done wrong this time.
Get yourself a copy of Why Does He Do That by Lundy Bancroft. It will help.
Know that this is nothing to do with you, it's HIM and HIS inadequacies that drive him to treat you like this.
He is only nice when he has to be, to hook you back in.
Now, many men become abusive when the partner is PG. He is ALREADY angry, controlling and nasty, he has thrown stuff at you, stuff that could have hurt you seriously badly. Imagine what he could and would do to you once you are in a really vulnerable situation like being PG, this could end your life. What about your 6yo, what would happen to him?
Please sit yourself down and see through the players here. He is not the person you agreed to be in a relationship with. That was Dr Jekyll. You currently have Mr Hyde. Detach the 2, Mr Hyde is a stranger, you have no idea what he is capable of, all you know is at best, he is not your friend, at worst he is your ENEMY. Don't let him have any inkling as to your plans, even if you see nice flashes, that's all fake, don't fall for it. Stay focussed, your one objective in life is to get him out of your life.
It comes down to who do you want to save, it's a battle, potentially to the death. Him or YOU? Have no sympathy for him, he has none for you. Expect all the manipulative tricks in the book to be thrown at you, plan for the worst, have escape routes in your mind, have people on stand by, have your DS elsewhere.
I know this is overwhelming, I know this is alien to you, but please trust me. I know I am asking an awful lot of you in a very short period of time, but please do it and we can all talk about it all after he's gone. I know there will be a corner in your mind that says Ah, it's not that bad, surely, we can get through this, all I have to do is not antagonise him, not upset him. But his demands will grow more and more and more each day. This is a battle that you can't ever win. He will never say, Ah that's it, you are perfect, he will never say I was wrong I'm sorry and mean it, he will never, ever be 'normal'
You will go on to see that what is being suggested is in your best interests alone, and with your utmost safety in mind. Anything I have suggested you do, can be un-done. But if he batters you, or worse, these things can't be undone and could endanger your life.