After I Transmigrated Into a Book, I Fell Into a Sweet Romance with the Tragic Second Male Lead

[Transmigrate into a book + sweet ancient romance + tsundere at first + doting husband later + childbirth] Su Hangyin woke up one day to find herself inside an angst-filled novel. On her very first day there, she was granted a handsome husband and even got to have adorable babies? Wasn't this the perfect start to the peak of her life? Who would ever go back after that? “I'm not going back. I want to stay with my husband!” One day, a bodyguard reported: “Your Highness, the Crown Prince, the eldest daughter of the Su family says she wants to make money and keep you.” “What did you call her?” “The Crown Princess, your Crown Princess. She wants to keep you.” “I don't need that.” The bodyguard thought: You're such a stubborn tsundere. I can't even call her by name. And you say you don't need it? This isn't a typical power struggle, nor is it about a strong female lead seeking revenge. It's just a sweet romance! One main couple and four secondary couples.