So... you haven't read the overview, that literally says you're playing as Jessie and missed the "female protagonist" tag on top of that? I also wasn't happy that you couldn't decide to let it happen or not, but this is not NTR because Jessie is the MC.
I don't think that's a valid argument. You're playing a game where Jessie is the main character, and you get to make choices that affect her behavior, but it doesn't come across as you actually being Jessie.
Thus for most people (at least most men probably) Jessie is going to be the main sexual interest. You want to control her actions in a way that leads her to interact with the people you desire in a specific way. If you're into incest, then you probably want her to hook up with her son, or potentially even her daughter.
But what you DON'T probably want is some random side character coming in and conquering her before anyone else, and without ANY ability of yours to stop it from happening.
So in that sense, it certainly feels like NTR for the player. Because you're forcing them to watch the player they're interested in and wanting to control who they hook up with, etc... you're forced to watch them hook up with someone you potentially really do NOT want them hooking up with. (Aside from how unnatural and forced the scene feels, as you've barely met this other kid and potentially have no interest in having him be anything more than some side character to drive a more important plot along, like that of his mother and Josh, etc.)