If you really really don't want to argue the point then don't argue it. You're right, romantic interest would be a better word for it. That being said there aren't any childhood friends in this game besides maybe Nestor and you can't fuck himI really really don't want to have this argument but its pretty widely accepted that it doesn't need to be someone actually in a relationship with the MC, merely a love interest is more than enough. Its pretty common in the generic "My childhood friend was stolen" stories that are all tagged NTR. Some guy fails to confess his love for his friend/crush and another guy swoops in and apparently according to most of those hentai writers, its first come first served with women so lol......
Again, not going to argue it so feel free not to explain any further....
yet. Just wanted to make a distinction, since marvelfreak said "people's definition of a sex scene can differ". NTR is its own specific thing, that usually focuses on the feelings of the guy getting cucked. What this game does is different imo.