Is hardcore flirting online a form of cheating? I've never felt the desire to cheat, pretty much don't even register other women have a vagina in a relationship as I'm happy with my partner. One night went downstairs for a midnight snack, saw a blinking message and curiously looked (felt guilty doing it but eh, curiosity). "I wish you were my homework so I could do you instead" to her best friend and some replies. Confronted her and to my point of view that's cheating, to her it was just how she communicated with her best friend.
I like the analogy of "You can get your appetite anywhere as long as you eat at home", at least in regards to things like porn, but when it's your best friend that you see randomly at any time? Fuck that noise.