@XeanLux It's because her situation is terrifying. She's essential stuck in an emotionally abusive relationship where there is no clear abuser. She doesn't understand when he will revert and everytime it happens she will receive scorn and her life will be threatened.
At the same time, she's gotten a taste for the (maybe fake) love that she's given and she's gotten woefully addicted. As we see from her perspective, the majority of her careful, concentrated effort is diverted towards how she can continue to maintain the relationship, with some cursory thought given for escape.
Add to the fact the she isn't an idiot, and is completely aware of the situation she is in, fully realises and feels guilty about what she's doing, and even realises that the hands that are caressing her cheeks will one find their way clasped around her neck, and that she's living on an uncertain amount of borrowed time.