as
Badjourasmix said, netorare is related to jealousy, humiliation. This idea that you need an ongoing love relationship does not exist. If you have feelings for your mother and a guy "steals" her from you, if you feel jealous, it is netorare.
Except that I think the staff understands that, if she took it with other guys, and the MC didn't see it, she doesn't know or that even after she was passed from dick to dick by everyone at school she is still available for the MC to pick up the remains , this is not NTR.
In my opinion it is NTR, but it can be questionable. It's just that I just don't have an interest in getting a spit resevator from other guys to put as my love interest. If that's not screwing up an LI, I don't know what else it can be.
But remembering, these are all assumptions. Nothing is clear, but it is the picture that Dev drew. It may well take all those black clouds out over LI. Or you can confirm what everyone has understood so far.
If it is confirmed that the picture is what we believe it to be, then I am taking the nearest exit.