As Lundy Bankroft says:
“He is not abusive because he is angry - he is angry because he is abusive”
He flies off the handle deliberately in order to be abusive, it order to maintain control. Not because he is losing control.
It has always worked for him and it continues to.
Your children are being abused and, worse, they are being taught that this is normal because it is their everyday and because you stay. So they in turn, will grow up to either become abusive or, to marry abusers themselves.
Not only do you need to get away from this relationship, you need to be very clear with your children that dads behaviour is not ok and that we should never stay in relationships where there is abuse.
Your children may also need therapy to process the abuse that they have been through.
Get away and give your children a safe environment with you at least half the time. His home might still be dysfunctional but at least they won’t see their mother being abused and staying anymore and will have a safe home with you.
It is not protecting them to stay, it is teaching them that dysfunction is normal. And, making them feel either obligated to protect you because you can’t protect yourself or, to join in their fathers abuse of you because they think doing so will keep them safe.
You need to be the parent. Get away from your abuser and make sure your kids know that we do not stay with bullies.