so basically here he is shocked both because he knotted a beta and because he is starting to realize that by doings so he will change his secondary gender and make him an omega. He knows this is wrong but succumbs to his instincts and keeps doing it until it's too late and the mc finds out. He forged medical records and isolated him from ppl just to keep this from him... just messed up all around. The mc gets mad and loses all trust in ml so he confronts him and they decide to take time apart. The ml gets smacked in the face with reality and starts groveling pathetically, after 1 year apart they get back together but he can't quite forgive himself yet, so he keeps on groveling even though they get back together. The novel is VERY clear on this basically being rape, and the reasons mc has for forgiving him after a whole year. It's also clear how much the ml regrets doing something so abominable. It's gonna take a while for the manhwa to get here though lol

Please spoiler below I don't mind spoiler because I am already regretting not marinating this and reading this ongoing ╮( ̄▽ ̄)╭