He's only afraid of the monster she has become... The beast has been struggling to escape from out of him since he was young. He tried to run from the beast, but It's hard to Escape the darkness if its in your mind. How do you escape your own mind? You can't. You will always have the horrible creature surround you. He wishes that he could stop it from escaping... But the only way to make it go away, is death. He is prepared to die for the sake of his angel and his own sanity. So with one quick rush of adrenaline he takes the plunge and jumps. As he's falling, he begins to remember his better days. The monster tries to take over, but he pushes it down one last time.
Two days later, the police find his body... No family was contacted, and nobody rushed over to the scene. When the paper heard word of the Opera Ghosts death,They asked why he would do this... But no one mourned his death for days to come. The moral of the story is you can't stop death. It always takes its toll on everyone. Regardless if they are loved, or not.