I agree. Seok Hoon will hurt for a while, and he will probably be distrustful of everyone - including Min Hee, I hope!
He is an intelligent man, and I want to hope that he will hear why the Geum family did what they did - after all, he was the one that grabbed on to Mrs. Geum's hand, and then insisted that they were his parents. They meant well, and while it's easy for us to say they should have been honest, he touched a nerve deep in Mrs. Geum's heart, and she could not tell him the truth. I hope he will understand that, and also remember that THEY were there for him, not Min Hee.