in the novel this is like his last resort to sleep with inha, he also quit working at the convenient store because he's planning to work far away with his friend which was the day after they slept together but inha basically force him to stay and he did.
the way he treat mc was also different and mc managed to slip away after a few days thinking ml was fine and while on the way to said work place inha contact him again, begging him to meet and mc give in. that's when it all went downhill.
Okay but like he lied to have sex with him even went as far as turning himself into an omega. He may know he's lying but it's still extremely fucked up. You can't just go around manipulating people like that. I get both sides. I'm just annoyed with the MC and his whiney bullshit lol like make up your mind bro

Lemme turn myself into an omega to fuck this guy. Oh he wants more? I don't want it now.