Oh, I'd just love to give you a big hug!
Let's get one thing straight - the person that we have to think of first is you. If you are not well or in a good place, it will affect the way you deal with your children and anyone else.
Don't feel that you have let anyone down by your decision to ask your husband to leave because quite frankly, it sounds to me, like you should have kicked this mean, selfish, childish person into touch long ago!
It doesn't matter what his parents think - you have to be doing what is right for you and he is not helping by trying to play the kids off against you with his sob stories, same goes for the women he works with.
I would guess that your friends and family have been fully aware of what he is like for some time and perhaps not wanted to say anything for fear of upsetting you.
You are set on a path that is going to be hard as you will feel that many people will be against you but with the love and support of your friends and family, you will get through. I would suggest that you seek some counselling, not to say you have done the wrong thing (if they try to suggest that, walk out and go elsewhere!) but to reinforce the strength that you have. May I add, this will be your own business, it will be absolutely none of your husband's business!