You've stayed through multiple attempts. 
I would strongly encourage her to stay in a hospital until her chances of trying again are slim to none. If she doesn't want to to do that and her family is willing to take over her care then I'd say it's safe to walk.
If you need to walk away for your mental health, I see nothing wrong with that. It's sad to be sure but not wrong. 

I'm not going to tell you to stay or go. I will say do what you think is best.