i completely understand in the moment why hong joo wanted divorce him but i wouldn't say he had an affair, it was her own thoughts that drove them 2 away. she barely gave him a chance and then when she married min joo it seemed like she was desperate but she gave him too many chances knowing well what he was doing. it sounds like im only blaming her but all 4 of them are to blame..
this did not seem to be the type of show where someone had to die