Right to brief it up as much as I can.
I was with my girlfriend for about a year before she ended it all, it was brilliant to begin with but towards the end she became very distant and not very nice to me, I stuck around hoping to resolve whatever was troubling her. She told me she wanted her freedom but a week later I find her with someone else, the person who she has always been a little TOO close to.
Ive tried to move on, when Im with my friends everything is great but when Im alone at home, trying to get to sleep or at work they are in my head constantly, it gets me so angry all the time and its not healthy at all.
I feel how you would expect (angry, upset, frustrated) I was honest, I would have done and did do anything she wanted and loved her as much as I humanly could yet she gets rid of me for someone who everyone feels is a bad trade for me.
I don't want to feel this anger, its affecting me too much and I want to be able to go to my favorite places with my friends without the hurt of knowing she's all over him at the same place.
Id just like to hear some opinions about the situation.

Takes some time to work through the anger, and put things in perspective. Accepting that she wanted another instead of you, is very hard since it was clear out the blue, but you did have a suspicion, and I guess you were right. Damn, that has to hurt. But to put it in a better light, she will probably do the same to him. Move on to better things.