I guess technically it's "avoidable" in the sense that if you do everything right then yeah it won't happen.
That is if that fits with your personal definitions (story starts out by MC being cheated on and then losing the next girl).
But what I meant is that there's not just one or two NTR scenes, it slaps you in the face at every corner.
And that's just not my cup of tea seeing that it seems to be the "default" choice - it's not "don't whore out your girl if you dont want it", instead it's "make sure to grind the right stats and pick the right chioce at every event or it will happen."
I'd disagree with the every corner bit.
The only ones I remember that have vaguely any ntr are Sasha, Alexis, Lexi and Aletta... Maybe Sam.
Sam is a background one... been a while since I read the intro, but last I remember MC likes/loves her but never dated her. Of the other four. Aletta is the shitty boss, haven't played the harem and reworked/completed office questline yet, so can't tell you.
Sasha wants to get it over with her ex... you don't have to play it right, if you just say hi, have one meal per day with her and do a compliment or talk with her, it should be easy, by the point she tells you about the hunk, to decide if you wanna go with her route or not... at which point getting to 51 lp is insanely easy. After she starts liking, she forgets all about the jerk or better yet... you make her forget about him. (with one exception, but it's up to you)
Alexis, on the other hand, is a bit trickier and is there for NTR fans, but you can still avoid that if you grind well enough.
As for Lexi... well, she's a whore... her plotline is to get her out of that life... or not, up to you... but you can as well just ignore her and tell her to fuck off if she's not the type you wanna date... same with Sam.
There's Kleio, Anna, Morgan, Hanna, Kylie, Palla, Lavish, Audrey, Bree, Minami... and many more others who have not a hint of NTR whatsoever... the Sasha event after 21 days is also... I believe, a one off. Still doesn't make you date her afterwards.