"Why didn't she just get out of there as soon as she felt uncomfortable? many people explicitly or implicitly asked.
It's a rich question, and there are plenty of possible answers. But if you're asking in good faith, if you really want to think through why someone might have acted as she did, the most important one is this: Women are enculturated to be uncomfortable most of the time. And to ignore their discomfort.
This is so baked into our society I feel like we forget it's there. To steal from David Foster Wallace, this is the water we swim in"
I have seen bad relationships from which one or the other simply cannot seem to withdraw from. I suppose it all comes down to what you are willing to endure.