Please contact Womens Aid here, they can also help.
What do you get out of this relationship now?. Nothing at all.
You are in an abusive relationship with your H and this is over because of the abuse he metes out towards you and in turn them. Infact your relationship was over the first time he abused you in any way.
There are no strategies for coping that will work with such a man, you need a divorce and asap, not in 10 years time.
What do you want to teach your children about relationships and what are they learning here from you two?. Would you want this for them as adults, no you would not. But they are learning from you both that this is how people behave in relationships and its no legacy to leave them.
He is probably "nice" to them and that also gives them mixed messages because they see you as their mother being treated so poorly by their dad.
Do not keep yourself trapped by thoughts of having to share custody with him, do you really think too that such a man would actually want 50/50. He is saying that to keep you in line, its an empty threat as such men do not care for the kids either. Re your children being further raised by a stepmother figure that is something you cannot control or do anything about so do not stress over that point to your own detriment. Its also no reason to stay and you now must step out of your own paralysis and be properly decisive about your future and that of your children's going forward. Staying as you are is no option at all.
Do not hang on for another 10 years; you really will become a shell of your self by then and your children won't say thanks mum to you for staying either.