Where did it go? (a love story with a happy ending)

I'm going to tell you a little story. How a girl loved a boy very much, and they were the best of friends, best friends. She lived far from him, but decided to move back home were she would be close to him. After all that, he broke her heart and so she moved on. Months later much later, he came back into her life. Now they are still friends, and like each other still, but there is no love. This girl loved him no more. Now she wonders were did the love go, how could she cry and hurt for so long? was it all spent ? did it die?. She looks for it when she looks at him, but is not there. She tried to find it several times and she never could. She asks herself if it was ever love? She thought it was, she would have done anything for it. Now she is happy and content, knows that her heart doesn't keep that love anymore. The question is how the heart changes?, how it knows and then it doesn't ?