Responses
If i'm not mistaken i saw someone posted spoiler from the novel that heegyeom actually has a crush on jaehan. His pov on the night he was drugged wish to "rape/sleep" with jaehan. So i don't think it revenge but more like possessiveness behind the good guy mask
so there'd gonna be flashback arc later? if that's what happened then this relationship is double toxic bru. one of them don't know love so he crushed the other person, while the latter also drugged the other person in order to sleep with him. they both needs therapy lol
i think at some point heegyeom is indeed in love with jaehan, plus they had a history of sleeping together once before they met again as hwadae/sponsor
but the fact that jaehan was the one who crushed his life and made him start anew couldn't be brushed off easily. he ain't no saint that will just forget and forgive it, moreover he's at the peak of his career at the time when the drug scandal happened. he might be in love/hate rls with jaehan right now. i'd despise jaehan to death if i were heegyeom
maybe deep down he's planning a revenge? he might know that jaehan likes him, so heegyeom kept sleeping with him to make jaehan fall harder, then dump him when he gets the chance