Hey Eliza....

Great question! I imagine you're gonna get a slew of different responses.

For my part, I think the difference between flirting and cheating has to do with intent. If you are vaguely aware of the boundaries that you and your SO have with regards to other 'interesting' people, then the line is drawn by your desire to cross that line. If you would allow yourself to cross the line, even mentally, I think it's a form of cheating. If you interact with another person, no matter how physically, and you are still within bounds, then I don't think it's cheating.

I have crossed the line once years ago and it still bugs me. The reason it bugs is that if my GF (now wife) and I had better communication back then, we may have had a fabulous 3some. Instead, it ended up with lots of unfulfilled lust and some guilt on my part. Thankfully we're better at talking now!

__________________
Sometimes I wanna take you down.
Sometimes I wanna get you low.
Brush your hair back from your eyes.
Take you down let the river flow.