The Li Family and the Bai Family have a close relationship, as well as all business engagements, with both families being similarly powerful.
Li Shuning disappeared and hasn't been found yet; canceling the marriage was understandable for the Li Family. After all, with their daughter gone, they couldn't keep dragging the groom along.
They could understand, but it left a knot in their hearts; after all, their daughter had only been missing for so many days, and they proposed canceling the engagement, which emotionally hurt them. They wouldn't want Bai Zihao to keep waiting as Shuning's fiancé.
In the storyline, the Bai Family can turn around and attack the Li Family, which is enough to show that childhood ties mean nothing; interests are the most important.
Li Shuning had already explained the situation to her parents.
Bai Zihao had a fiancée yet flirted with another woman, leading to the woman causing Li Shuning to be kidnapped, almost not returning.
