Why does Misty Man 2 sleep with Girl 2 in Korean dramas?

In Korean dramas, the reason why Hellmin Yu, a man in Fog City, and Xu Enzhu, a woman, are together is to get revenge and destroy her.

Xu Enzhu and Lan, a female student, are in the same school. Gao Huilan was the man of the hour, and Xu Enzhu was jealous, but she was unable to change, so she became jealous. One night, Xu Enzhu found He Mingyu and told him that Gao Huilan had been violated by the shopkeeper, but it wasn't.

Lan and He Mingyu explained that he didn't listen and impulsively clashed with the shopkeeper, which led to his imprisonment. After he got out of prison, he knew the truth, so he wanted to get back at Xu Enzhu and did it.

Besides, Xu Enzhu is a jealous and hateful woman. She was jealous of Gao Huilan and tried to destroy him. After Kevin and Gao Huilan met, Xu Enzhu tried his best to destroy Gao Huilan by framing him.

He Mingyu loves Gao Huilan very much. Knowing Xu Enzhu's misdeeds, he wanted to destroy her in this way and let her taste the pain of destroying others.