Boy rant

Okay do I had a boyfriend for one year and we were great I guess called the honey moon faze just kind of left. Then I started to notice how he started to give more and more attention towards this friend of mine. I told him if you like her just let me know so I can let you be with her and he always denied it and it always hurt me when I saw them together so I decided to end it and now they are both together. Should I be upset at myself, the girl or the guy.

Btw the girl has been my friend since 2nd grade and she knew that I had always liked him.