Okay so I read this thread yesterday. Sure enough the members here are extremely nice and understanding. Their words should help comfort you. However TheInsane I wanted to share my view on this.
Now I kind of understand where you are coming from. I am under the impression this was your "first love." Sure enough those breakups hurt and seem to stay with you the longest. The main thing you neeed to remember though is, its all pointless man. If you are going to get upset cause a girl left you and she has moved on, well....go get laid
I have been through this situation. My "first love" was when I was back in high school. I met her in 10th grade and we have dated off and on for over 4 years now. It has been a lot of good times and bad. Tons of arguments and great sex. To this day I still think about her, however I refuse to let her get me down. You just have to remember things will change, you will move on and find someone new. Just gotta give it some time man. Besides the sex relationships aren't all they are cracked up to be. Constantly having to make sure your signifigant other is happy, and you aren't doing anything they dislike. Not to mention the arguments! Have you ever gotten into a petty little argument that you never thought was possible? Well guess what they are when you are in a relationship.
Here is an example:
(this is true too)
It was my graduation party and my "first love" was there of course. Now I am sure we were dateing, I could be wrong. Anyway that is besides the point. I was out front of my house hanging out with a few friends and I was smoking a black and mild. Sure enough this girl I've been mentioning (my "first love") came out and saw me smoking a black and mild. These were her words and I quote! "Seeing you smoke that black and mild was like seeing you kiss another girl."
Sure enough that moronic statement of hers fuled a huge fight between us. Since then we have still been bickering back and forth from time to time. We eventually got back together after awhile but this was short lived. The last time we broke up (a good solid 6 months or so ago) was because I am a "drug addict" and other bull-**** excuses on her end.
So anyway, sorry for such a long post. It can basically be summed up with a few words.
Man up, stop worring about it and move on. You will bounce back, and the next girl you meet will probably blow the other one out of the water. Trust me. I've seen it happen first hand.