So Charcoal went on to have sex with Junwon again and imo, there isn't actually wrong with that in accordance to their situation and relationship. They're only fuck buddies after all. Also, in ch 54, Myeongseon told Charcoal to only sleep with him and him only when Junwon is not around but now that Junwon is actually back then that agreement comes to a halt for the mean time. I do agree though that Charcoal needs to get his shit together fast, realize his feelings for Myeongseon, and actually break it off with Junwon for good. He needs to realize that the foundation of their relationship does not come from a place of comfort and love but rather suffocation.
So Charcoal went on to have sex with Junwon again and imo, there isn't actually wrong with that in accordance to their situation and relationship. They're only fuck buddies after all. Also, in ch 54, Myeongseon told Charcoal to only sleep with him and him only when Junwon is not around but now that Junwon is actually back then that agreement comes to a halt for the mean time. I do agree though that Charcoal needs to get his shit together fast, realize his feelings for Myeongseon, and actually break it off with Junwon for good. He needs to realize that the foundation of their relationship does not come from a place of comfort and love but rather suffocation.