I'm so very sorry to hear about this. You've come to the right place for support. You might get some replies that tell you to do things you might or might not want to do here. So please listen to you heart and do what YOU feel is best for you and your family. We are here to support you in whatever you decide.
First.....is the a habitually thing with him and other women?
Why is your mother so against him?
In my opinion, you both need to go to councelling for the sake of ALL. Not just the kids but for you and him as well. You definately want to leave or have him leave if this is in anyway ABUSIVE. If it isn't then I believe ya'll have some issues that have to be worked out. Leaving isn't always the answer. If at all possible both of you stay at home and work this out. And as you talk and start working toward a common goal. FIXING THE PROBLEM
then if at any point you decide you need time apart then one of you can go. I believe if it comes to that, then he needs to leave for awhile. Leaving right now just puts distance between you both and can lead to other things as well. If he leaves now then he has the opportunity to do things that he couldn't do if he stays at home with the family. (Ex. go to bars, being w/other women more easily than if at home, having no one to answer to) If he just stay there while ya'll work on this then those options aren't accessible to him. I would not even let the word DIVORCE come into our vocabulary right now; that word can come up as a last resort. I'm not even saying continue in the same bedroom. Just stay under the same roof. It's much easier to work this out if it can be with him there. ALL THIS IS OF COURSE IF HE'S NOT ABUSIVE TO YOU OR THE KIDS. If he is then he needs to leave RIGHT NOW.
I'm gonna let you answer these questions and I'll come back and talk after I have a better understanding of your situtation. Take care and I'll be praying for you and your family.
Be good to yourself