<human>: Summarize the given text in a few sentences.

We broke off our exclusive thing early April which seemed alright with me because she didn't want to be in a relationship her freshman year.  We hooked up the week after, so I was feeling totally fine about us. 

However, I shortly noticed that our 3 month stint was marred by her feelings for one of her friends.  I know she's 18 and maturity shouldn't be expected.  But out of all the girls I've been with, she was the only one I could see a future with.

She was sweet and great for the few months we were together.  Now she is doing all that with another guy, and honestly it just hurts.  My appetite and sleep have been heavily affected. I really wanted to be with girl, but this guy ended up seeing her more than I did and she must have felt that it more more of a natural feeling with him.  

She is totally one of my best friends and now I'm sure that I shouldn't hang out with her, or even really contact her. She really wants to stay good friends with me, but now I'm feeling like I can't.

How have others dealt with someone you really care for leaving you basically for someone else? Thanks guys I could use the support right now.
<bot>: Girl I was exclusively seeing for 3 months moved right on to someone else.  How can I deal with this hurt?