Strange gimmick but I do enjoy the smut scenes, which are frequent. Mangaka's art style is pretty good as always.
At least she's fucking someone visible during that chapter, lol.
With that said, NTR? Eh...she's a massive sex fiend. The summary of the story mentioned that while MC & FMC live together, they're fuck buddies who will slowly become romantically intertwined as the series progress. I think the rich dude in that chapter asked her if she has a boyfriend and she said something along the lines of waiting for the MC to get serious.