I kind of want to share a personal story since this hits close to home:

I am really ashamed to admit this but around 3 years ago, I felt and acted the way she did before and over the exact same reason of being rated a 7/10 (except the feelings were directed towards on particular person I was in a rather complicated relationship with). It got to the point where I was breaking down the concept of beauty to a science that even the internet couldn't analyze further, forcing no-makeup no-filter selfies onto him to prove him wrong and contemplating plastic surgery while badgering him about how many points I'd improve if I fixed X. I really did have an accumulated ego which was why I disagreed with the rating that I got, but I also had this fucked up mentality that I wouldn't get cheated on if he realized that I was prettier than most of the girls he went for and just wished he would think that way.

I'm not saying it was justified or healthy for her (or me) to act that way, and I'm not completely sure if she feels the same way I used to, but as disgusting as the actions were, there might be a reason for acting that way other than just being...crazy. Well, it's still crazy but the reason might be a bit more understandable.