For those going into this manga there is a sequel to this with the same name the story doesn't end here. The sequel does start off with another character and story but the two story should meet up later in the story. I reccemend following the two story side by side as you don't lose much as of now. The translation for this is probably be faster than the actual chapter releases for the sequel and thus by the time this is finish translated the sequel should tie up the cliffhanger we see at the end of this story.
(Speaking of which please would someone get to the sequel too please)
The fmc was literally crying and pretty obviously unhappy, is it a unhappy ending, hell yes. A bad ending, up for debate. but I just don’t see it as NTR. I’m probably just too optimistic. The sequel will confirm if it really was ntr or not
Glancing at the raws I couldn't find the "NTR" in the last chapter that has everyone so worked up. I can't read of any of the text so I could be missing something.