Seme was a virgin until this chapter. I think Yuta was obsessed with him because he didn't sleep with him. I don't think there's anyone who wouldn't think Yuta was handsome. But then in the bathtub, they only kissed. And that could have surprised Yuta, who could seduce anyone because everyone wanted to "have" him. But Seme was in love with his boss at the time and refused Yuta. That's why Yuta thought Seme was different from everyone else, which could have caused the obsession with him. In one of the first chapters, Seme says that he's not interested in sex with men. This is my theory. I apologize for using the word "seme" all the time, but I don't remember his name
I think they slept together in past and Yuta felt Seunghyun's gentleness so here he is but now he knows Seunghyun is same as other dudes he has been with(just my theory but you never know if author have completely different story in their mind) and someone pls tell me are these official translations bcuz I got brain damage after reading this episode