For anyone wondering if it's still rape / sexual assault - because of that initial consent (which was also just in that one last case, because there were many other instances where he didn't get Jeongin's consent at all before that) - when Jeongin was *begging* him to stop later on.
It most certainly *is* sexual assault, both by law and common sense. (Though I suppose in manga it's become so common that people are begging the other to stop and being ignored that one almost tends to not even consider it anything out of the ordinary there anymore... Σ(¬_¬) ).
Also, Jeongin may have been a bit of an asshole in the beginning, but all the things Seunghyun did were on an *entirely* different level. In the end, Jeongin was still being constantly threatened and coerced, and he did absolutely *nothing wrong* by doing his best to escape that situation - he had nothing to apologize for on his end. (Come to think of it, ironically, I don't seem to remember Seunghyun ever once apologizing or admitting fault for any of the *diametrically* worse shit he pulled.)
I don't know why, but with the last chapters, I'm starting to feel low-key worried for some reason that there's a chance the author might intend to spin this in some way like that he was actually not the one who pushed Minwoo, and supposedly "not forcing" Jeongin (because, of course, asking that *one single time* in the entire story if he really wanted to do it - while violently forcing himself on Jeongin, ignoring any protests, and doing whatever the hell he wanted pretty much every single other time both before and after that in the story, makes the sex "consensual"). And that Seunghyun was therefore imprisoned "for things he didn't do" because of Jeongin - so that they've supposedly "both hurt each other" and are supposedly "even"... or even make Seunghyun appear like some kind of victim in all this... I really, really hope that's not the case, because that would make me seriously pissed. It's a very engaging story with beautiful art overall, so I really hope it doesn't turn into one of "those" stories ┗( T﹏T )┛