I think its more like, despite having 'feelings' for taeiu, he truly doesn't give a shit if what he is doing is hurting him. Prepping him is a boring delay of his own pleasure, so why would he bother? And with taeiu going full Stockholm syndrome, there's really no need.
Ikr !! I just cant with these two
Spoiler
In the the first book ( passion)taeui not enjoying so much but don't worry in dasim( second book ) taeui enjoying it and love the segg with ilay so much until he cry out of pleasure...
Spoiler
Nah ilay just don't know what a prep is lol ( in the past when he having one night stand he just shove in his dick don't bother to prep so whenever it's man or woman their anal/vagina torn and bleed out but he doesn't care just finish his pleasure and toss them aside )
but in the novel this chapter ilay just put the lube then move slowly but in the manhwa we get robbed.
No no ...taeui don't really develop Stockholm syndrome (100% sure, novel reader here)
2nd book?? Please provide us with link
What pisses me off is that there is no sex scene (anal) where taeiu enjoys it. Its only pain and suffering for him which concludes Ilay is bad at sex.