if u go back to the chapter where euntak asked lee dojae to go on 3 dates with him, he asked dojae to not see anyone else, he said both of us can't see anyone else during the 3 dates. i agree that it's not cheating but logically if he was going to break the agreement might as well refused altogether. so euntak wasn't mad that dojae used to be a player, but rather because he broke the agreement. it doesn't sit right with me on their very first date after dojae took euntak home he immediately slept with someone else, u might be ok with that but maybe euntak isn't