Stockholm syndrome
the thread on acoholics taking hostages brought Stockholm syndrome to mind. We do have the choice to leave or stay but the explaination below pretty much sums up why some of us hang around longer than others. Take out being threatened with death (though I'm sure this has happened to some here) and it might ring some bells.
The Stockholm Syndrome comes into play when a captive cannot escape and is isolated and threatened with death, but is shown token acts of kindness by the captor. It typically takes about three or four days for the psychological shift to take hold.
A strategy of trying to keep your captor happy in order to stay alive becomes an obsessive identification with the likes and dislikes of the captor which has the result of warping your own psyche in such a way that you come to sympathize with your tormenter!
The syndrome explains what happens in hostage-taking situations, but can also be used to understand the behavior of battered spouses