Per what Gixi said, it’s very much subtext rather than text even in the books, so it’s one of the things I’ll be talking about in Part 2. As for the fiancée, Nihuang— no, nothing bad happens to her. The drama pushes the love interest angle more than the book does (although ultimately I don’t think that changes the central importance/vibe of the JY/MCS relationship). In the book, she marries another guy who doesn’t exist in the drama.

I haven’t actually watched the sequel drama so I don’t know if she married anyone in the intervening time?