Hi Just4me
I felt so sad reading your post.
The person you loved, is gone, yes. It's hard on the heart, as we so wish things were different, but, he is not healthy for you or your children. To hit you, especially whilst pregnant, and throwing things at the children - completely unacceptable and downright despicable. It would only progress. You and your children are best without him. From what you've shared, he hasn't been "present" for some time due to drug use.
Keep him far away from you and the children. Contact your DV team and find out what your options are. First and foremost, safety!
Think with your head, not your heart, as he will attempt to make you think he's the "old him" - he isn't. He will try to weedle his way "back in" - don't fall for it.
Once the dust settles, you and your children will be just fine. As long as you remain the stable one for them, the children will adjust.
I'm sorry this is happening to you, bit you will come out the other side knowing your strength.
Much Love
Bute x