Help With An Exit Plan?

I am finally reaching the point now where I need to face facts and realize that I can't change him and he is not going to change. Unless something drastic happens to him of course, but I'm not holding my breath. So now, I want to focus my energy on an exit strategy. The thing that is completely overwhelming about trying to come up with one is that we have two very young children. As in, they're not even school going age yet. We are very stretched when it comes to finances right now, so the thought of us splitting up is just so terrifying in terms of how we will cope financially. As it stands, there's no way we'd be able to live in/pay for two separate houses/apartments. And we're still in the very hands on parenting stage, so I am just so scared for how difficult it will be looking after two kids  (I work full time). Can anyone give advice who's been through this and who doesn't have a huge amount of money to throw at the problem from either side?

The sad thing is, I should have rather exited before we had kids. Hell, before we even got married. But I naively thought things would get better. Once we were married, I thought kids would help with the situation...OH how wrong I was. I look at my two innocent children and I feel so so sad for them, and so so guilty for doing this.