mpuddleduck - I hope you don't mind me posting, I just wanted to say that I think you are being brave and strong through what must be the hardest time of your life.
FWIW you are making the right decision although it must be so hard for you to see that. You are being emotionally and physically abused and that must have damaged your self esteem and self worth.
You need support and this thread is very supportive of you, everything everyone has said is true your husband won't change, your relationship is irreparably damaged.
I have worked in several environments, and still directly work in an environment dealing with domestic violence, he won't change.
You sound like a loving,caring and good mum - please consider this - domestic violence between a couple is an indication for children to be placed on the child protection register, violence that the children have witnessed is an absolute indication and an indication to remove the children.
If I treated a woman who was a victim of domestic violence who then intended to return to the family home with the children and partner there, the police would be involved with a view to take out an emergency protection order to protect the children. He will not change, his behaviour will escalate and it will be all your fault (so he will say). You can not change him but you can protect yourself and your children.
Please I don't want to shock you, or undermine you in anyway, it is apparent your children are your main priority, but they will be far more damaged in the long term by witnessing their fathers violence towards you than their parents living apart.
I hope all goes well on tuesday, you are doing the right thing, watch him leave then feel the relief. Try not to worry for your children they will be ok.