It's a good point, but, given that only tantalisingly tiny nuggets of information are thrown out to the public about the royals, we will naturally spin layers of narrative over and above 'fact'. These stories will inevitably be interconnected across all the different players.
But, why do we want to know so much about the royals in the first place? Contrast that with public interest in other prominent people. Absolutely no-one wants to know about Johnson's kids and wives/women, or Cameron's children or the Blair kids. Across the pond, how much interest is there really in the Kushners, Ivanka's wardrobe, Chelsea’s activities we all know about Hunter but he is in a different category? So, it is specifically the royals that everyone wants to know about, because of their blue blooded exclusive genetics, I presume.
By the way, wasn't it Giles Coren who first tweeted about the possible affair (tweet promptly deleted, but not before some papers picked it up)?