I totally see your point, but remember that Wonwoo only knows Yoon as a womanizer and about his “little ritual” before a game. So it is impossible for him to believe Yoon at this point. Then, Yoon right away invites him to a booty to the hoody night and well that didn’t help either lol
I mean wonwoo has mention it throughout that there's a big gap between their standings and it gets in the way of thinking that yoon could even possibly like him or even if he did how far could the relationship get? His reaction is pretty normal considering that Yoon never opens up and is bad at communicating. Simply wanting to explain days after the uh "event" he should've sent a message or something on the same day for damage control . That said they ain't dating either so
I agree he should have contacted him that day, or said anything when the lady was there. It did say Yoon tried to call later but Wonwoo wouldn't pick up.
Yoon waited days before contacting him though. Wonwoo did wait for him to explain by staying up the whole night waiting for his call. Would you care now? of course not. And Yoon acted high and mighty like I'm doing you a favor by explaining this much since we're nothing. You just seem pathetic at this point for hoping, that's why Wonwoo just wants to cut tie once and for all. Moving on with his life.
I honestly thought like Wonwoo was a bigger ass this chapter. Yoon Geon wanted to explain the relationship between him and red haired bitch but Wonwoo stopped him out if pride. Imo Yoon Geon said the last bit about meeting for sex because he was pissed Wonwoo was acting indifferent(not that it makes what he said right). I think Yoon Geon is more aware/comfortable with his feelings than Wonwoo.