I don't think ohn decided just like that, from the beginning you can already tell that ohn felt more for seo woo than he did Jae woo. The amount of time each twin spent with ohn didn't matter. I noticed cuz before the big reveal, Ohn's accidental interactions with seowoo was the one that stood out to him the most. That one moment that got seowoo stuck in his mind. Jae woo mightve been the one who started it, but seo woo's charm was the one that pulled him in.
Examples: library, swimming pool, that time they ran into e/o drunk, the first movie date. Even Jae woo noticed he was more susceptible to his presence after that.
But all this doesn't really change the fact that Seo woo was a coward at first and that Jae woo deserved better
The situation really was unfair to jaewoo
I also don't think ohn lead them on, they both chose to pursue ohn, and ohn spent time with them to see who his heart called out to, honestly ohn's better than most for immediately telling Jae woo how he felt about seo woo after he realized, some would try to push it off, causing the other more pain.
Either way Jae woo deserves better and he should get his own happy ending
Am I the only one who wished Ohn got with Jaewoo. Like, SERIOUSLY. Seowoo asked his brother to step in cause he was too much of a COWARD to face his crush himself. If you’re gonna have a standin, don’t get upset when they fall for your crush! No wonder Jaewoo fell in love with Ohn! And then like, Seowoo basically reaps the rewards of his younger brother’s hard work. Like WHAT?! If you like someone that much you shouldn’t lie to them. And Ohn was annoying too. He spent so much time with Jaewoo, only to choose Seowoo. Ohn led them both on and then was like “well, Seowoo is better since I hugged him and decided”. DUUUDE! You don’t decide who you’re in love with JUST LIKE THAT! And tbh like Jaewoo was just helping out his big bro WITH NO COMPENSATION. Honestly Ohn shouldn’t have tortured them like that. The best outcome would’ve been for him to refuse both of them. The twins deserved better