He ultimately broke her. Take example of her family; they used and abused her from the jump and even after running away and disappearing They somehow show up and harass her once again. And never recovering from that trauma your whole life will affect your life drastically. No matter how hard you try, you will constantly be reminded of it. So when he came into the picture and entered her world as like a saving grace and someone she could have that was on her side. Ultimately, she depended on his stability to keep her afloat. Now I know it's not healthy of course, but it was working for the long run until it wasn't. So when the tables started to shift and become unsteady so did she. As for the him becoming more involved time and time again with that woman, did we honestly think she was going to just let it slide? After already voicing that she's uncomfortable with it. I'm sorry but the second he lied to her face without a second glance was when he lost her. There was no more trust. There was nothing. And him coming to the rescue for her with her family was just crass. On top of that, NEVER TALKING ANYTHING OUT. For her going back, that's 10 plus years of history that can't just be dropped overnight. Especially since he kept her afloat. So her realization of hating him more than the woman shows that even the person that she kept close like family can make you feel absolutely horrible. And if anyone was in her shoes, I don't believe for one second you could just drop the person you've had by your side for years and be okay even after what he did.