Maybe it was his mistake. He loved her too carefully, knew too much, was entangled too much, and couldn't explain it clearly. He said he would wait for her forever, but when she looked back, she was filled with heartache. How sweet they were, how deep their love was, and how painful it was in the end. He never married, and she missed her so much that she became ill. This hurt more than being injured, and her depression was deep.
Intention: It's all a dream, in the end it's all in vain, and when you wake up you're left with only heartache