Often it is the fear ... abusers work hard to deny their victims the ability to see a future beyond the abuser. Cult leaders do this also, and slave owners in the U.S. had an extensive system to make my ancestors by the millions feel this way also. There are certain things that can be done to any human being ... but what the abuser cannot know in advance is whether or not certain individuals have a core that is too strong to perpetually be in that position and not realize: eventually, that kind of person will begin to see a future without the abuser, whether that turns out being a Mrs. Harriet Tubman, a Mr. Robert Smalls, or a Mrs. Hugh Howard (of which, in my own family, there were TWO in the last century). Methods vary ... but we are made such that one person may not assume the place of God over another forever. The person who tries may not be ready for the consequences when enough is enough!