Kinda weird to left this out, was kinda important imo.
It shows that JK really wanted to know if it could work with a male beta. He hurt the beta and he stopped.
That scene also connects to the scene where JK is worried about hurting JH when they have sex for the first time (since JK forgot for a moment that JH is not a beta but an omega)
Guess the manhwa wanted to make JK a total virgin?

Am I tripping?? Didn't Jae-kyoung have sex with that beta in the novel? I mean, they didn't go all the way, but I remember that he tried to put it in but was too big for the beta o_O