Bebsy, just take another look at the thread title YOU CHOSE to start this thread with. Somewhere inside you, you know how this is going to shake out, but you're still defending and denying.
You're saying it's not going to be your problem anymore, but you're also saying it's not so easy to turn on a dime, get someone out of your life... but you know better. These are just choices you make, or choices you default on by not choosing. You've got a long life ahead of you still, and you can either cut and run (RUN, dude. Run.) or you can hang out and still be associated with this and have it affecting your life.
You've got a choice to be done or not, and it's all on you. It's not on her, her family, your mutual friends, or even your family telling you to get out, or The Bore and all our advice. It's just you, only you, as it ever has been.