no because the english use of the ntr tag is for when an anime/manga inspired media contains cuckoldry and you can't cuck someone when there is no relationship, sharing is generally preferred as opposed to netorase (which I've seen shortened to nts to make a distinction from ntr) since there's no confusion with ntr when that's the case and sharing requires a proper relationship, atleast fwb, otherwise it's either prostitution or a casual one off hookup neither of which would count as even sharing.
I would not count the relationship described as one close enough to consider sharing since she doesn't trust you, I might change that opinion once I actually get around to playing it
I will agree vanilla sounds like false advertising tho