Based on the raw current chapter. I bet it’s moon seop(otaku).
Spoilers
Because a year ago, Jinyoung was in date with a girl while he was in a friends-with-benefits relationship with Jihan. In this part, Jinyoung says he's in love with Jihan, but because he's an only child, he follows his mother's orders (they're rich, by the way). So, he decided to meet up with the girl and break his promise to Jihan (they had planned to meet up that night). Sadly, Jihan went to the hotel and saw Jinyoung with the girl. Jinyoung ignored Jihan and said to the girl he was just a junior, which broke Jihan's heart because he was already thinking about starting a relationship with Jinyoung. Sadly, that part happened. So, with these scenes, it really implies that Moon Seop is the main lead (I think).
I haven’t read it yet but who’s the ml?