TLDR; All women are like that.

As we all know women crave attention. Women will go out of their way to prove to themselves, Chad, and everyone else around them that they can get dick whenever they want. The better looking your girl is the better the chance is that she will fall victim to this mentality.

9/10 slut dates Chad, who could literally have any girl at his college. Chad commits fully, she see's this and takes advantage. Her hamster starts spinning, and her thoughts begin to move towards: "Why commit to Chad when I already have him locked up? I can have any guy I want, I don't care how attractive, rich, and charismatic Chad is, I want the attention to fall on me, so I will cheat to let everyone else know that this relationship is about me."

The woman didn't even try to hide the fact that she was committing the infidelity. Why hide it it right? That goes against her nature. To put this into perspective for you, Chad is one of the most desired men at the university and the woman in question is up there as well.