I Took My Sister’s Match and Married the Doomed Crown Prince. Now I’m Empress, and My Whole Family Kneels Before Me

[Both Reborn + Swapped Marriages + Mutual First Love + Disabled Buddhist Prince] In her previous life, her half-sister stole her betrothal and married into the Crown Prince's household, believing her beauty could make the prince abandon his Buddhist vows. Shen Shiyan was forced to marry the son of a disgraced official. Everyone waited to see her make a fool of herself. But in just one year, she became a general's wife, admired by all and living in splendor. Her half-sister, meanwhile, was beheaded for secretly having an affair. In this life, her stepsister opened her eyes and immediately demanded to marry the son of a disgraced official, leaving Shen Shiyan to marry the disabled Crown Prince. She happily agreed, because she was lucky: whoever she married would turn their fortunes around. She treated the Crown Prince's injuries, helped him reclaim power, and waited to take the highest seat in the land. But can someone tell her why the Crown Prince, who had always kept his distance from women, suddenly broke his vows?