That’s why he’s beating mc up when Guwon’s NOT around, to try scare him off. He’d never have the balls to do it front of Guwon, and he knows mc likely won’t tell Guwon what happened. If MC did tell Guwon, it’d probably cause a shit show, Guwon would be torn between believing new arrival lover and long time loyal hound, and mc would be outing himself as Guwon’s favourite, making himself more of a target for bullying or just straight up isolation (ie from the townspeople who are scared of Guwon)
Actually it perfectly works the opposite way, especially with these psychos. If people like these deeply wants to win the approval of a person, anyone close or near that person will be seen as a competition or an obstacle, that includes a lover. In fact a lover may be the worst thing ever, because that means Guwon's affection and attention will be focused on his lover. That's even more reason to eliminate the lover.

It’s no shade but you can tell when the author is pulling something out of their azz. If they want to win Guwon’s approval, and hold it above all else, wouldn’t it make sense they respect his lover? Or at least act like it? I don’t see it ending well especially with the affinity he already has for the MC and the fact that he already openly protected him. Maybe it’s on me for thinking a toxic yaoi would include logic but at the same time I understand why the hounds would be irrational people. LMFAOOO