Divorce Support Forums: he won't let me out of marriage

Help! My husband has adult add/adhd and refuses treatment and has quit counseling all 3 times we've tried. He's also narcisistic (sp?). I've gone alone, had myself/hormones tested, and even took antidepressants and I'm the one who's okay! I can't take this 8 year marriage anymore and I'm ready for him to be gone for the sake of my sanity. We've been emotionally divorced for several years now anyway.

The problem is this is his second marriage so he can't afford more child support (child from 1st marriage), we have 2 young children ourselves, and he keeps telling me I can't make him leave and he'll never sign papers! I know he'll make my life hell when I try to fight him so I just haven't had the strength yet to start. Right now I'm saving up my money and trying to put my ducks in a row. Any advice?