When two people have to let each other go. Dispite the fact that one of them loves the other one truly. The girl or the guy in your case, decides that the two of you are not compatible for each other. Hopefully the two of the people can remain friends, though that is hard for guys to do, because we hold on. But always remember, there are more than 6 billion people on this planet. So though you may not want to hear it, the chances of this person being the one, are less than winning the lottery. I know it's tough but you have to move on after a break up.