My Senior Sister Is Fiercely Protective

Ye Fan was on his way home one night, planning to give his wife a bouquet of roses, when he saw with his own eyes that she had been cheating on him. Only then did he learn that their marriage certificate was fake, and that his wife had not given birth to the child. Yet the baby in the swaddling clothes was his own flesh and blood... In that moment, Ye Fan broke down. Whose child was it, after all?