<human>: Can you condense the text into a few key points?

Me 19/m and my ex 18/F dated for 10 months, she left for college, joined a sorority, hooked up with other guys within two weeks, whatever. I never went with NC and her and i decided that when she came home we would be together and when she was away we wouldn't. Sounded ok at the time. 
Anyway, in the three months she's been gone I have gone to the gym more and look fucking great. She has gained 15 pounds and lost almost all of her friends outside of her sorority. I have slept with another girl. She's a voctorias secret model, need I say anything else? My ex has been with multiple guys, all of whom ditched her after sex.
She came back yesterday, we hung out, had sex, it was meaningless. After, we were hanging out on her couch and I was texting my other girl and she was snapchatting some guy and I realized I'd rather be anywhere else with anyone else rather than there with her. 
She asked me to tuck her in, I said no and just left. She seems bad but I really don't care. I don't care who she hooks up with or what she does. The bottom line is I deserve better. I don't want to be a hook up buddy. I mean It's fun but I just don't care about her at all and I don't really like the person she has become.
I don't know if this means I'm over it but I'm not angry or bitter, I wish her the best I just don't love her or want to be with her anymore. Feels weird.
<bot>: My ex came back, we hooked up, realized I don't have feelings for her anymore. Not sure if that's a good thing.