From my observations I wouldn't say its a love triangle. I feel like TJ ( neck tattooes dude ) is the one that took Ian's virginity and they've known eachother for years so they somehow became sex partners before TJ left Ian for a while. I don't see it as a love triangle because TJ said he doesn't care if Ian fucks anyone else as long as Ian thinks of TJ when Ian cums. Joseph seems like the possessive type. He def found Ian attractive and found him special in some kind of way that he wants to keep him all for himself.
It's like when you have a classmate that looks straight out of Pinterest and you're like, "damn...j really wanna befriend her" so you do everything you can to be that classmate's friend. Except in this manhwa, Joseph seems to want Ian all for himself, whether it was for his looks, how tight he is during sex or just the effect that Ian left on Joseph
Thank you so much, i totally understand you
Is it a love triangle, i didn't get it
Spoiler
I see that the uke think about the other gangster dude, but ian in love with the uke, how i can't think about a love triangle here, it's confusing