Wheat Fragrance, Mangzhong

Sangyan turned into a widow known to bring misfortune to her husband. Despised by her in-laws and disdained by her own family, she volunteered to retire to a remote estate to live out her days. At this moment, she caught the eye of a tyrannical emperor with a strange illness - being near a woman caused him unbearable itching and relentless vomiting. 
Hence, the 26-year-old emperor had never favored any of his consorts, let alone sired any heirs. The imperial harem constantly pressured him for offspring. The common people also yearned for a royal heir. When they learned that the tyrant held affection for Sangyan, the widow with the ill-fated destiny, the entire nation opposed their union. 
Eventually, the entire country pleaded with Sangyan to bear children for the sickly and tyrannical emperor... 

Beauty widow with a deadly fate VS Emperor with allergy to women

Chapter 303: The Oil Runs Out