Speaking of realism and behaviors, this is certainly one of them. We all do it...talk about other men and women like this...even when we are in a relationship. But there is a lot to what you are saying about world-expanding. Nyx has talked about it in Discord. And it is a constant battle with how much to expand but balance people getting upset about it approaching the NTR realm.Nyx just seems to love to tease with pseudo-NTR-ish stuff. Not sure if it's her just trying to broaden the world so that everyone isn't about the MC, but between the girls all findng some teacher hot, Erynn going off about John (who is likely her dad) being hot, Iris grabbing Emily's ass, Erynn's escort services and naked modeling, and pretty much everything with Val... it's definitely kind of odd.
When it comes to real life, I cannot stand this game that people play with each other. Flirting with someone else when the one you really want is right there. Why play with jealousy when you can just be an adult and tell them how you feel? Fucking blows my mind that grown adults still play this game. So, it is obviously naturally occurring...and highly annoying.
BTW, Erynn is just doing what models do. They take photos in and out of all types of clothing. They go to events as hired arm candy. And she hates it.