I hear you. It's so sad that we get caught in preserving the familiarity and comfort of the madness we live in, even when we know it's madness. I fell into that same trap with my WXH.
I am SO much happier without him. But in the course of our marriage I lost parts of myself that I am slowly picking back up along the way. I have my amazing DS, and I have this totally awesome boyfriend now, I'm rocking my grad school classes, I have a wonderful support system of family and friends (including some awesome ones from this site)... I think I'm okay.
You'll get through this. One day at a time. Sometimes, even one minute at a time. But you'll get there.
ETA: Be GLAD you didn't have children with this schmuck. I have one DS from my marriage to the schmuck and he is just as much an idiot now as he was then.