That’s the answer to the question, “Why didn’t you leave?” at least for me.
Hurt people hurt people. I’m empathetic to a fault. I’ve learned that is what has the potential to hurt me, the perceived weakness that is empathy. I figure people need someone to be that for them. Few people, I’ve learned, actually appreciate or even respect that. I have had to not allow myself to get close enough to anyone to feel that way. Or, if I do, I have to keep it to myself, distance myself from the person (so they don’t use it to hurt me), and work on dismantling any feelings I have/had for them.
For me, empathy is a shortcut to misery. No one cares that I care that much.