Honestly....after reading this thread, it kinda seems like you won't be happy until someone says, "Yeah, go ahead and boff him!!"
You sound like a smart woman. You know that staying with an abuser is no good for you or your kids.
If you are in the US, you can contact the National DV hotline. Here is their website and phone number. They can help you get relocated with your children.
http://www.ndvh.org/
1-800-799-7233
P.S. IMHO, sleeping with this guy will only complicate your life....and not in a good way. All the other problems will still exist - and you'll likely have some new ones.