Ohhhh my fucking God you are so wrong. (I dont care about netorare just to be clear)Bruh... that is not how NTR works...
NTR is broad BY definition XD
Don't go assuming what it means by how westerners use it, go by it's actual meaning.
NTR (Netorare), literally translates to "To be Taken from.", it has never, and will never mean cheating, cheating is not NTR, and NTR is not cheating. However cheating can be NTR, and NTR can be cheating, but they are not mutually exclusive nor are they synonyms, that is a classic misunderstanding of the term, usually from those who assume its meaning because of the few stories they have read.
Also even by the weakest and most loose meaning what is in this game still counts as NTR, it just happens off screen, let alone the full meaning.
Back to the point "To be taken from." doesn't require much relationship level, childhood friend, and simple crush counts, all the way to lover and wife, and they can be taken from in ANY way, whether it be male female, human, not-human, animal etc. and method doesn't matter either, it can be cheating, it can be rape.
As for your "NTR is for when the partner willingly cheats".... bruh... you do realise that 2 major types of NTR REQUIRE them to be raped? there is rape that stays as rape, and rape leading to cheating (whether that be via mindbreak or they just start liking it).
So please, don't go assuming you know a word, when you don't even know it's LITERAL meaning.... which fun fact, is the words meaning. Cause by your definition, the japanese themselves have been using the word wrong since it's inception XD And about 80% of NTR isn't NTR.
Netorare means by definition EXACTLY that your wife is cheating on you with someone else. She has sex with someone else WITHOUT your consent.
Netorare is the exact same as cuckolding. Which is without consent.
And ONLY netorare is covered by the F95 "ntr" definition. NTR on this site means ONLY netorare.