Gentlemen, let's get the facts straight?
She made a mistake? She made a big mistake. But put yourself in her shoes, fuck.
Imagine losing the love of your life because he sacrificed himself to save you? Some people don't know how to deal with grief well, only those who have lost someone precious know how hard it is.
This is a work of FANTASY, which means it is apparently possible to bring someone back to life.
Knowing this, wouldn't you do anything to get the love of your life back? Some people wouldn't, and some people would. Camus is one of the people who would.
It even fits that saying "the 'hero' sacrifices you for the world and the 'villain' sacrifices the world for you".
Again, I'm not exempting the shit she did because of this, what I mean is that it is TOTALLY UNDERSTANDABLE that she made such decisions. And the problem is that all this shit could have been avoided if the MC had simply told her that he was alive (he himself acknowledged this)...