There was a time in Xiu's life when the question 'Why her and not me?' ruined Xiu's peace and left her in an emotional turmoil. Perhaps, that was the biggest question that pushed her so deep in depression that she forgot the way out.
But only now did she understood how Zhou Jinhai was never her happily ever after. If anything, he was merely that 'once upon a time' in her life. A hurtful and painful once upon a time.
It was painful when she wanted to hate him but loving him had turned worse for her. And when there was nothing left for her to do. She did nothing indeed. She couldn't bring herself to hate him but she definitely forgot how she loved him.