
Yeah, that's what his answer should have been, maybe, but they just started dating. And he was only being truthful, even if he shouldn't have been, how would he have known that? He probably felt that his actions should be enough, and wasn't aware that gunjoon was even insecure about it until gunjoon blew up.. Of course he would be feeling upset and defensive after his boyfriend just basically called him a slut and accused him of meeting with other people.. I feel for gunjoon, but this still could have been avoided if he just mentioned his concerns or directly asked jungseok if he liked him.. Instead he let random people get in his head and spiraled until he hit his breaking point.

Like, thnk about it realistically. Gunjoon has heard rumors about jungseok, and noticed people come up to him often. He hasn't seen him in any weird interactions with people, coming out of an alleyway or something, but random people who he doesn't know, and isn't even sure how well jungseok knows, can come up and say literally anything about his boyfriend, and he will believe it. He laments over how he knows nothing about jungseok, but doesn't bother to ask him anything, or initiate meaningful conversation. Jungseok doesn't either, but he isn't insecure because of rumors he's heard so he doesn't think it's a big deal.. Probably because they just started dating.
all of that and he couldn't directly ask if he liked him. Only making accusations without explaining, either... Gunjoon...