Strange tightness

There is a strange tightness in my chest that I cannot understand. I secretly look at her profile sometimes. She's perfect and I won't understand if anyone didn't love her. If I was a guy, I would love her. Yet, they broke up. They did because of distance. They must have been in love. They are perfect together. I don't understand. They may have broken up. But they must still share a love. They still love each other, don't they? How can you love a person one day and then stop the next?