At heart, I think I'm probably a faithful monogamist. Morals aside, I don't think I'd have the energy to sneak behind my partner's back with another person — or spend all my time balancing various lovers in a polyamorous relationship.
That said, there are few things I find more toxic than common attitudes towards (heterosexual) fidelity. It's heartbreaking to me that there are so many who don't trust the one they love to have friends of the opposite gender. If you doubt them that much, why are you with them at all? Also, what does this expectation of betrayal say about your own self esteem?
In theory, it should be a big green flag for a boyfriend and a best friend to get along well. However, that wasn't the attitude many viewers had when they saw one TikToker post about the 'sibling'-like relationship between these two people in her life.
Showing multiple clips of her friend and her partner lovingly play fighting with one another, much of the internet became convinced that they were cheating right in front of her eyes. While a minority reasoned that this was an overreaction, plenty more disagreed. Maybe we should all stop projecting our own bad experiences onto others, even if we turn out to be right.