Yep, on the blue path here, it doesn't really fit. It's usually the way this goes though in other games though. If there's a "loyal" path, that's one thing, but here you've already got the fooling around that's unescapable. The only thing you can do is limit how much of it there is - so there's no "loyal" path as it would be seen in other games, IMO.
To be clear, I'm not saying that you'll get the NTR in the blue path if you keep saying no, as that would be a betrayal of the paths, although the dev could easily take it that route, if he's willing to risk the wrath of players.