C.N.
Hi, B.. I'd just like to start by saying that I am praying for you and your husband. I have never been where you are so I won't pretend I know what you're going through. The best advice any of us could give you is to just pray. Give everything to God, get in the word of the Lord and revel in it. You've gotten some great Christian advice in other posts so follow that and KNOW that God has a plan for you. As someone said before, FIGHT! If you've given all you can and an end to your marriage is inevitable, then at least you can rest easy that you did all you could do. Your daughters will have so much respect for you and you're teaching them a valuable lesson in not giving up. However, if you need time to separate then your husband should be the one to leave. If he wants out that badly then tell him to go but the girls stay with you. You've made it your life's work to care for them and you shouldn't stop now. Besides, there is something going on with him and I'm not sure you'd want your kids exposed to whatever that is whether it be an affair, depression or something else. If he is that determined to get out of your marriage then make him do all the hard work. Don't succumb to his demands. It sounds like that's what he expects. No court is going to give him custody of those girls when you are their primary caregiver already. He'll just have to pay more child support with that better paying job and it sounds to me like he knows that and is trying to avoid it.
I pray you can save your marriage. Be strong for yourself and for your daughters. They're worth it and so are you.
Blessings!