In a tricky spot and not sure what to do next.

The leadup: Had a two-month long emotionally intense fling with a co-worker. She had just broken up with a bf after 2.5 yrs and insisted on being single for awhile, but was cool with "seeing" me. She quit her job to go to school, which made it a little harder to keep things up, but we managed to stay in close contact - I went on vacation for a week with little contact, came back.

Instigating Event: Got back and hung out with a girl she knows I have a history with, and she got super pissed and jealous about it. I tried to apologize, wrote her a long handwritten note, came off really desperate. Then NC for a few days - she said because of the way I made her feel hanging out w/ that other girl, she realized she needed to push me away. Things are rough.

More Instigation: After NC two days, I gchat her a good joke that breaks the ice. I coolly convince her and her friend a few days later to go to a day party, and that party goes well - I come off funny, don't talk about anything dramatic, pretend like all is good. When all seems good, I find out she's starting to hook up with this douchy frat guy that works in my office (and lives in my apt complex).

Where we are now: I'm livid. I text her angrily the next day about it, tell her its a huge turnoff and i would've expected the decency to not go after my own co-workers. I even tell her the guy is a tool, so I'm coming off pretty jealous. NC right now for two days. I'm still extremely angry about it but I still want her back.

What next: I'm just hoping there's still a chance - I know she liked me, and we had a great two months together. But she's different than other girls ive dated - was homecoming queen, mrs. popular her whole life. Can get any guy she wants. She can move on easier than me.

Advice appreciated.