No-win

A sense of being trapped in a no-win situation. I know the person I'm waiting for is unstable, possibly dangerous, and I will never feel comfortable around him. I also know that he would not be willing to let me leave the relationship and that anyone who helped me leave would be in danger. I consider trying to disappear, but know I would be pursued and never be able to feel at ease. I keep thinking through all the options and can't find any solution.