She's not listed as an LI. I'm not sure how this got misconstrued, but it seems most of the headache here is revolved around this.
Maybe this thread will help you out:
https://f95zone.to/threads/ntr-in-area69.72019/
Basically it doesn't matter what you as the writer intend, or what you write the MC in the game to have as relationships, etc.
What matters is what the PLAYER wants, for whom the MC is just an avatar. If the PLAYER wants to pursue a given girl, then it is his feelings that matter. If he feels that he wants a particular girl, even if he can't have her yet, or maybe ever, but then he is forced to watch her be taken by another person in the game, HIS feelings will be of jealousy and anger that he could not prevent it.
It's best to never show such things, even if it is implicit, for example if you have a married woman in the game. In that case you know that the woman is probably having sex with her husband, and you're trying to steal her away from him, or at least make him the cuckold by doing netori (note that that is different than netorare. Netori is where you are the bull taking the woman you want and forcing the other man to be the cuckold.) But still you don't SHOW the player this sex happening, because the only reason to do that is to evoke those feelings of jealousy, anger, etc.
The key point here is that this is a game where you, the player, insert yourself into the game through your proxy avatar, the MC in the game. It is YOUR feelings that are key, as YOU, the player, decide which women you are attracted to, which you want to pursue, etc. And you should never be forced to watch the women you potentially want to pursue having sex with other men.
A lot of players get upset because devs ignore this and claim that because they wrote the MC to have certain feelings that it's not NTR, but that misses the point. The MC's stated feelings are not what matters. It is the feelings of the PLAYER that matter, because it is in the player that those feelings of jealousy and anger are going to be evoked and they're the ones that are going to be mad at you and complain because you showed them a girl they hoped to romantically or sexually pursue at some point in the game, having sex with someone else.
And no, just saying "well, don't play that part then" isn't a good solution unless you literally make it completely separate content that you make very clear is NOT CANON, for example how Power Vacuum does it with their "What If?" bonus content that is very clearly marked as non-canonical and released as separate stand-alone volumes:
https://f95zone.to/threads/power-vacuum-what-if-vol-8-ntr-what-why-games.36240/ )
Keep these ideas in mind and you can please your NTR loving fans with the separate, non-canonical bonus content, while still having your main game keep the bulk of your fans happy. (You're never going to make everyone happy, but you can at least avoid some of the obvious pitfalls.)
