I think Shinru doesn't betray Tae-eui. I tried to translate it and It comes off as Shinru do that sh** because he want Ilay to not go near Tae-eui (because Shinru like Tae-eui). Tbh, first time i read the translation it comes off as Shinru betrayed Tae-eui but later when i translate several panel after that, it shows that Tae-eui feel sorry because Shinru do that sh** so Ilay won't go near him and bothering him.
But well, i'm not actually fluent in korean and i translate it solely from google translate so i could be wrong with my translation.