Like 11 divided by zero, I don’t have a definition of cheating in the OP sense. It’s undefined and meaningless.
Lying exists. Bad faith in the form of “lying by omission” exists. “Cheating”? No.
It’s only cheating if you’ve agreed to some kind of exclusivity with “Nina” beforehand.
There’s a famous Korean pop song about this very situation - the title could roughly be translated as “A Match Made in Heaven.” It’s about a guy who is growing uncertain about his relationship and guiltily agrees to go on a blind date set up by a friend. Of course when he goes out on this blind date it ends up being his girlfriend. The song ends up with them laughing and saying “I love you.” :dubious: The message is supposed to be that it’s fate that they’re together, but hey, if both of you are shopping around for something else, I don’t think that’s a good sign for your future.
That is not cheating. Peeing is for losers.
So it’s like “The Pina Colada Song” in Korean?? That song always cracks me up, because both partners set out to cheat, it ends up being each other, and they end up laughing about it! Ummm, no, that’s not how I think that ending would go in real life! 
Clearly, you’ve never tried one of my pina coladas. 
Your pina coladas will save a failing relationship?? I thought you needed Long Island Iced Teas for that! 
And we didn’t. But in past relationships, exclusivity was kind of assumed. Last night, though, we set proper expectations. We’re dating. That’s all.
It was very strange hitting on other women while she was in the room, I must say. My style was a little cramped.
I’ll second that. The “what is cheating” conversation is a necessary one in pretty much all relationships. Some don’t mind things up to and including #10 on the aforementioned scale. Some can’t deal with an exchange of fully-clothed backrubs. It’s specific to the people involved and what matters with it is that everyone involved understands and is okay with the negotiated parameters. It’s a good-faith agreement. Cheating is violating the inherent trust, therein. That’s my thought, anyway.
It definitely depends on the person. And everyone has their own little quirks. In a lot of couples, it’s common for the guy to be okay with his g/f messing around with other girls, but not with guys, for example.
Well, the secret to my pina colada is the roofie. I suppose you could apply that to a Long Island, but it would lack a certain tropical je ne sais quoi.
There we go. All I ask is that I can be in the room while they’re doing it, if for some reason I can’t actually be included.