Why is it that only Zheng Fei in Grandpa Four's life has feelings for snow dance?

One problem may be grandma Wu Xue, whose divination is invalid. She only knew that Zheng Fei was his legally married wife in history, but she didn't know who the heart of the warrior Lanling belonged to. You have to read grandma's exact words carefully. She said Zheng Fei was the only woman. Another possibility is that it was like this, but the snow dance and the warrior Lan Ling crossed and changed something. I thought it was the mission of the goddess to help the warrior Lan Ling save the whole life. At this point, compared with the doomed fate of the goddess and warrior Lan Ling, Grandma's prediction is still much weaker, because this is Wu Xianzu's mission since ancient times. )