i personally think it’s a thing of the other two are so far removed from the idea of BEING exclusive that they don’t realize, at least one of them doesn’t, that they’re exclusive and are also TOGETHER together. like we see in the very beginning that hwayoung is of the same mindset as the other two, but that mindset changes the more he interacts with gyuwon, he wants that monogamy. i think its not out of character for the other two to be so unaware of what hwayoung is feeling bc 1) they barely meet anymore (for what i’m seeing) and 2) they’re still continuing what they were doing from the very beginning, meaning their mindset hasn’t changed from that.
maybe this didn’t help, i just thought i’d pitch in to the conversation ( ̄▽ ̄)
My inyerpretation is, they do know hwayoung and gyuwon is a couple and thats the reason why they get more on edge with hwayoung, especially the blond one. He is envious of how hwayoung got to have a normal relationship in the kind of life they have and seeing how our main leads are so lovey dovey with each other. Its rare for that in their world, and a syou mentioned, they swap subs around but hwayoung's never into that and he stopped going in the club. So take it as agand for example. You cant leave as you want, you cant have a normal life but hwayoung was able to do so, and happily at that. So the rest cant takeit (mostly the blond, he'z had a love hate feeling with hwayoung ever since cause hwayoung is kind of superior jn a lot of things idk)
I absolutely agree with your interpretation as well. Which is why I'm more irritated by their behavior because it's not like it's impossible to have a normal relationship with a loved one, they don't even bother trying instead take it out on hwayoung and gyuwon due to envy. Bunch of parasites #-.-) hope they get their own happiness too soon but rn (╬ ̄皿 ̄)凸

So dom and sub are sort of like transactional relationship. One dom can have multiple subs. The sub has only one master, but they may also switch if the dom no longer satisfies them. Or they can play with multiple doms, I guess depending on their obedience. Overall, purely pleasure is exchanged and the relationship sort of ends there.
In the story, they talk a lot about passing the subs around between the friend group. And they continue to think the same for Gyuwon.
Now my confusion here is. Do they not know the difference between a boyfriend and a sub? Like...a boyfriend can be a sub, but not all subs are boyfriends, right. So are they just purposely trying to get with gyuwon to piss hwayoung off or do they genuinely not understand the concept of a boyfriend??? You dont "pass" your boyfriend/lover around to other people.
I just find it so confusing these people look like they genuinely have no understanding of a exclusive relationship. Which is weird because you can be into bdsm but still be aware of how the world works, right??? Lol
Or maybe it is me who dont understand how bdsm works and what they're doing is just normal routine, even if the sub is a lover? Cuck play is a thing ig but it's so fcking clear atp hwayoung isnt into sharing ╮( ̄▽ ̄)╭