I agree with you. I also felt sad when I saw his smile. I don’t know if you noticed, but her smile was also forced. It’s honestly very sad. I hope he’s introduced to someone better suited for him soon. I always like when authors give the second male lead a new love interest, it livens things up and usually makes the story better knowing they can find love with someone else.
Yes because at this point in his life if he doesn’t meet someone that will completely overwrite SuAe in his mind, I fear he is destined for deep depression… this is so sad. I just wish for a woman with a bright sunny personality to come and save him from all this. He needs someone who will love him unconditionally for who he is and not as an afterthought.

Eunhyeok has been doing what he can to protect her on the side not to mention the amount of intention and restraint he carries not to overwhelm her. It reminds me of a conversation my best friend and I had on new year’s eve—that sometimes you feel like nothing is happening despite all your prayers or manifestations, but in reality, there are strings being pulled behind the scenes. It correlates with Su-ae in a way that her anger is valid, especially considering Eunhyeok’s disappearance—something he still has yet to properly explain to her. But from a reader’s point of view, to see the way she treats him can feel quite harsh. But still, as I said, justified.
For Dohwa, to give him credit of pursuing her and not giving up until she's settled, he is great in a sense. But I also agree that he needs someone—anyone else besides her as his love interest. Clearly, the fl and ml have something to address between them which makes things complicated for him. But seeing Su-ae's monologue just further proves to us that she still doesn't see him in such a way a person could interpret that they see another person as a romantic interest. If anything, it breaks her heart to see him smile while continuing to pursue her, especially when she herself is still trying to navigate her dilemma at this point in time.