How to get over some one

All righty. Well I was going out with a girl for 2 years and not going to lie I loved her. She was my everything. Things weren’t working right for awhile though. I went on a trip for a week and I figured out that she had hung out with this guy a lot while I was gone. She told me everything about it though. Still I know it is bad but I was doubtful of her. In the back of my mind and in my heart I know she didn’t do anything because I know she wouldn’t hurt me. I think I mean as much to her as she meant to me. That is when everything bad came up. We dealt with it for awhile but six days after we had been going out for 2 years I broke up with her. It was one of the hardest things I have ever done. I know I just flushed everything down the toilet but I thought that was the right thing to do. I thought I kind of had to. I really didn’t know what else to do I guess. A month after being broke up I thought I was doing really good. There was this girl that liked me and I liked her. I know I wasn’t totally over my ex but I had to tell everybody I was. I ended up getting screwed over by that other girl but I was ok with that. After that I kind of figured out how much my first girlfriend really meant to me. I mean still to this day which it has been like I guess 2 and a half months she is still always on my mind. The only bad thing is when I was doing good she was doing bad. Now it is the other way. She found this other guy. He is a great guy and all I want to do is see her happy. I mean like no matter what. I guess I would rather see her happy with me but you can’t always have everything you want. It is just so hard for me right now. I think today it finally clicked that I have to pull away from her though. I think this means like talking to her on the phone and at school and things like that. I mean a simple hi and things like that aren’t bad but I just can’t take I guess not having her. I wish she was mine again. It is so hard to hear her talking about that other guy or hearing other people talking about them. All I can do is smile and shake my head. Act like all that is nothing but knowing it is eating me inside like no other. I just get so sad and I think maybe even depressed when I think about her. I was just wondering for one if there is anything anybody has to say about that. If any one could kind of give me their thoughts I guess that would be appriciated. Do you think I should pull away like all the way? I mean I want to be her friend still but I don’t know if it is physically healthy for me… It tears me up inside to think of not having her in my life but I don’t know how much I can take of seeing them together or hearing her talk so good about him. I want to be there for her. I just don’t know what to do more than anything. If some one has been through this can you give me some help please. Thank you.