I'm actually glad that the ending wasn't something overly grand or spectacular considering that the whole series stayed simple through and through.
Very nice read overall.
The problem isn't whether or not there is NTR bait, it's just that it's an overly used unpleasant troupe that's used to extend the story. The troupe is ever more so unpleasant when it so blatantly clear that the MCs' will end up together making arcs like these dumbfoundingly predictable and...