I have come to realize that emotions get the best of us; both male and female. I honestly want to say that once emotions get control of males, it is actually harder for them to get a grip on it all because we usually don't deal with emotions as much as females do, so we are kind of stuck in a phase where we don't really know how to handle it.
So, when people say move on or do the same to her, I know it can be EXTREMELY difficult to do such. I am not going to pretend that it is easy; because plainly, it is easier said than done. But, it will take just sometime to realize the truth, get your logical sense back, and fight away the emotional thinking of your mind and heart.
I am assuming, from your thread, you are not with her at college. I graduated college a few years back and from experience, I know, that there are girls that stick with their boyfriends or they go off and go crazy. A lot of girls tend to get their minds changed a bit while in college. They almost feel a sense of liberation and want to experience it. They go off and do things they normally wouldn't do. For instance, look at all those p0rn sites with girls in college doing those crazy (yet awesome) videos. We all know them, but a majority of them wouldn't be doing that were it not for that "liberating" experience.
From what you are saying in your post, I feel she might be just feeling a sense of independence and wants to explore this feeling. You can attempt to reel her in, you can attempt to sit down and talk with her to make her understand, or you can let her do what she desires.
I hate it because it does suck. I think all PUA's out there have been destroyed by a woman at some point in their life's (myself included). Sometimes the most obvious thing is the hardest to accept as fact.