Life has never been the definition of perfection for him. To him, happiness does not exist, it is just a simple word without meaning to it. He had convinced himself to believe this since he was a small innocent boy. Never has he once felt the feeling of happiness, maybe it was normal to him by now. He thought that nothing could change his sorrowful mindset, until she came.
He never knew how much she could change his emotionless world. Even though he wanted to have her forever that was not ever going to be possible. As soon as happiness came to him, it suddenly left. Why? It's because forever is relative.