Is Dong Goo really his son or is he just assuming? Cause Yoo Mi still hasn't confirmed anything. But if she really is his mother, how could he treat Dong Goo like that (giving him to her mother instead of taking care of him for 3 years) when he’s so cute T^T

But they look cute as a family :O

I think they explained it in episode 10 or 11, but he really was just assuming. Donggoo is Yoomi's brother.