Mysterious Boss Is too Clingy

To save her seriously ill brother, Wendy Cassia resolutely replaced her half-sister and slept with a man in his fifties while she didn't know that she slept with the wrong person and gave birth to the two cutest little angels in the world.
Four years later, when the mysterious man appeared in front of her and asked her to take responsibility, Wendy Cassia was stunned. "Sir, we don't know each other. Please don't do this!"
"If you don't know me, why does your child look so much like me?" The man was furious.
"Mommy, don't listen to his nonsense. I am not like him at all!" The boy, who looked like an angel, made a face deliberately and turned to the man, snorting, "Go away! Mommy can only be mine!"
The man: Very good. This boy is definitely his son.