That's where the choices come in, surely? If you don't want the NTS, you don't choose the options leading to it, and the same if you don't want NTR? The only issue is the slight overlap at the start, I guess, but that's probably just where you start getting into it and then pull back, in order to start off the NTR path (because apparently there are no other ways to start such a path...).
Ah, the words of someone who only watches the sex scenes and skips through the rest...
So far at least, everyone is optional. I think the only exception is the actual MC/FMC together, but you might even be able to opt out of sex with the wife, I can't remember. For content, if you mean specifically within a scene (like can you avoid anal), we've not got that far yet, relaly. Other than that, there's a forced voyeur scene, where you get a few frames of someone having sex as you walk past an open bedroom door.