Responses
https://booktoki469.com/ you can find the novel here, the name of the novel is place to be.
I think around episode 5 and episode 6 in the novel, and in the manhwa we are in chapter 10 around MC's birthday.
https://booktoki469.com/novel is the link to the novel.

Make no mistake, the MC is not a rebound. In fact, ML’s yandere tendencies, something he didn’t even know he had himself, tend to skyrocket whenever MC is concerned.
Beginning to half of the novel starts off with the usual drill with what you see in the manhwa, you can take your time to enjoy the scenes without much worries for the MC. Ui-geon DOES have feelings for Jun-young since high school, but Jun-young and Kwon Kanghee, the other friend, has a thing going on between them as well, and there was no room for Ui-geon. Despite this, Ui-geon had never once forced himself on Jun-young, and he even took initiative to bring them two together. I did like that they took the time to explore Ui-geon dealing with the aftermath of his unrequited love, and MC may be gentle and nice, but not weak. The MC depicted in the manhwa is exactly what you get.
I won’t go too deep into details, but there was a point when Ui-geon realized Chi-Young was THAT student in high school who said he knew he was gay, and he’s the same as him. The confession attached to that line also meant Ui-geon knew about Chi-Young’s feelings for him, and Chi-Young DID confess to him, but also made sure both of them understood he has never been the type of person to covet someone or something beyond his means. Chi-Young is rejected here.
So the two, despite Ui-geon’s rejection, continued to spend time together, and unbenownst to Ui-geon, he was actually falling for Chi-Young, and falling HARD. I’m talking about wet dreams, confusion, horny for Chi-Young, the works. If anyone is curious, no, it’s on a completely different level compared to his feelings for Jun-young. If Jun-young was like a still calm lake, then Chi-Young was a raging tidal wave that causes lose his marbles.
So MC has been working odd jobs all this while to pay off his loans, and he was bitten in the neck by a prostitute while giving her a car ride back, and girl even bit his nipple. So Ui-geon? Naturally loses his shit when he sees the teeth marks, and it drives him crazy FOR DAYS to the point that he DOES THE SAME THING to Chi-Young and he tells Chi-Young they will now have sex. Yeah give him a bit of credit in that he managed to at least hold onto SOME semblance of sanity long enough for Chi-Young’s consent. NGL some people may consider this dub-con... in the manhwa, I'm pretty sure it'll be super hot, can't wait to see Chi-young being pounded to oblivion.
Next morning, Chi-Young wakes up and Ui-Geon isn’t there. He leaves because he had commitments to go back to his hometown to spend bday with his mum. Ui-geon naturally loses his shit AGAIN, and did I mention that before this, he punched Jun-young and Kwon Kanghee for having a part in Chi-Young’s odd jobs that led to the bitemarks? Yeah. So he goes back to Jun-young’s place and started losing it, before Jun-young tells him the truth (he told Chi-Young later he regrets telling him so quickly cos he wanted Ui-geon to suffer more.)
Ended up Chi-Young didn’t see Ui-geon that morning after sex, because Ui-geon was busy and he PAID OFF THE ENTIRE LOAN. So later this part is all about Ui-geon and Chi-Young navigating their relationship, they eventually talked it out after a series of small misunderstandings and revealed everything to each other. They became a couple after Chi-Young realized the implication of what Ui-geon said, that he wants Chi-Young to spend 80 years to pay back the principal (he said it in a joking way, this means he wants to settle down and be married to Chi-Young)
Ui-geon even admits to himself that this is part of him that he never knew existed, that he didn’t know he would lose control so much around Chi-Young. So that’s the gist of the entire story, I just read it so dumping everything here in one go before I forget details.
I’m still going through the side stories, have finished maybe 3/4 of it but tbh I’m not very motivated to complete it because all the tension was in the main story, and almost disappeared once they’ve settled as a couple. I think it’s one of those works where the manhwa would probably enchance the story so yeah, enjoy the ride.
EDIT : WAIT, the author wrote Passion? OKAY I GET IT NOW. Dude was channeling light-version Ilay the whole time lolololol. No really, even in the side stories, he was hovering possessive and eagle eyed if BOTH Jun-young or Kanghee even talks to or about him on something, you'd forget dude ever crushed on Jun-young in the first place.