I wish I knew what to tell you. BUT, if you've been unhappy all thru your marriage, what makes you think that if you stay, things will change? If nothing has changed all these years, they're not going to change now.
UNLESS, you two go to marriage counseling. Is there a chance that he would do that -- or that it would help? I don't know what your issues are in the marriage, so I can't say if marriage counseling would help or not. Are you being abused? If you're being abused, GET OUT. Do NOT stay with anyone who is abusing you, whether it's physically or emotionally/mentally!!! Abuse is abuse!
Being on your own IS scary. I did it for the first time when I was in my 50's, and believe me I was scared. I didn't know if I could support myself or not because I had a house and I had property taxes to pay.

When you don't make that much, it's darn near impossible!
Are there children involved? If there are, you HAVE to consider them too. Taking them away from their father will hurt them. So think LONG AND HARD before you do this. Make sure whatever you do is in their best interests.
I wish you the very best. Please let us know what happens. We do care about you. God bless and take care.. Hugs, Lee