I just don't get why this bothers you so much. It seems like your upset is more revealing that you realise.
I regret that using the term 'mainstream media' now seems to be a marker of being a Trump supporter, becuase it's not without validity. The mass, corporate, media has always tended to include a lot of sloppily-reported fluff stories. And they are generally very bad at reporting anything involving science or statistics.
This is just some story they like because it involves sex. It might be a valid study, it might be a bit of dodgy bad science (of which there is plenty about, especially the 'human sciences'), I'm not interested enough to care.
Who gives a ****? People have always lived in 'unconventional' relationships, and people have always cheated on their partners.