Reborn to marry, the short-lived prince lived a hundred years

[Double Rebirth + Sisters Swapping Marriages + Marriage First, Love Later + Two Pure Ones 1v1] In her previous life, Meng Tingyue swapped marriages with her nominally legitimate sister, Meng Qingjiao. She married the ailing Fifth Prince, while Meng Qingjiao married the Crown Prince. Who could have imagined that the Crown Prince, once the emperor's beloved heir, would die young? Conversely, the Fifth Prince, whose life was predicted by the imperial physician to be imminent, began to rise to prominence. Not only was he healthy, he emerged from the vying princes to become Crown Prince, gradually ascending to the throne. In her next life, her legitimate sister refused to be swapped with the Crown Prince, insisting on marrying the Fifth Prince, hoping to reap the benefits of becoming Empress. Meng Tingyue watched with amusement as she plunged into the fire, only to marry the Crown Prince instead. She wanted to see what would happen without her...