When I was a much younger person, it was nearly impossible for me to counsel any woman to leave her husband. I'm much older --and thankfully wiser-- now.
Planning is imperative. Often, just having the plans in place make the situation less strained, and sometimes gives the woman power to cause change in the relationship. You can't change another human being, but you can make them want to change sometimes.
I'd like to say directly that safety is key. Always have an emergency plan, some safe place to go the instant you need to get away from harm. If you can take some time, set yourself up financially as best you can ahead of time (yes, even someone who is poor can manage some things that will benefit her).
He probably already has you confined and without support or friends; you need to have some (secret) things to rely upon...
Here's a good link:
http://www.womansdivorce.com/leaving...e-husband.html