I've heard that people stand in bad situations because a relationship like that gets turned up by degrees. It is said that a frog will jump out of a pot of boiling water. Place him in a pot and turn it up a little at a time, and he will stay until he is boiled to death. Us frogs understand this.
So I put up with bad behavior in the name of loving the way I thought you were supposed to love.
A relationship could be a place to hide too.