How do I escape this controlling woman?

You need to get out before you dig in any deeper. What's done is done and if your family winds up finding out you just have to sit and talk to them and if they love you they will get over it. This woman is using the fear you have to keep you on her leash. Release the fear. You don't need her for ANYTHING, and you deserve better. I don't know exactly how you can escape, but if worse comes to worse bring in the police. This is blackmail and psychological abuse