<human>: My GF of 9 1/2 years (we are both 26) and I broke up two weeks ago. I'm still not sure exactly why, and it hurts like hell. This may sound really dumb, but I have no idea what to do. For me, the relationship wasn't over. 

We were having minor communication problems, and I kept making time, to the detriment of my academics, to spend with her and to make sure I had time to talk to her. She started hanging out with a new group of friends (a reddit meet-up actually), she began spending all of her time and energy with them. She was super flirty with some of the male members, and I started to get a bit suspicious. one night she didn't come home. I was so worried! I couldn't even get a hold of her via cell. She showed up the next morning and said that she had fallen asleep on a friend's couch. Found out that she was actually cuddling with him all night in his bed, and that she would have cheated on me, had he made the first move. I told her that she needed to figure out what it was that she wanted, and let me know. Turns out she wanted to live the early twenties single life. lots more details if you'd like them. Just ask.

Since then we have fully broken up, and I am just distraught. I have no idea how to transition into this new world. I thought this was "the relationship". To make it worse, she doesn't seem to be having a problem with it at all. I feel totally disposable, or as if there was something that I was inadequate in, which I know is unfair to myself, but that where I am at. 

So...how do I transition out of this, move on, and become a better person for it?

Give me the gist of the text in a nutshell
<bot>: GF of ten years broke up with me. feel like the ground is gone from beneath my feet. advice on how to move forward?