If a tree falls in the woods (next to an investment banker cheating on his fiancee with a whore), does anyone hear it?

I was having drinks with a straight male friend from business school a couple weeks ago at a no-name bar in Soho. My friend got a call from another guy that we went to school with asking where we were, and that guy decided to come join us. I didn't know this guy well in school, but he always seemed nice enough. He is doing very well for himself now as an investment banker at a big firm, and investment bankers always intrigue me so I thought he'd have a good story or two.

So he shows up and we have a round, and then another round. By this point I am aware that Investment Banker has got engaged (to be married) since we graduated. However, during round 3 he is becoming very interested in most girls walking by. At some point the conversation moves from some girls fine ass to hookers. Now I'm the only gay guy here, so I feel like the outsider in what I assume is the normal ritual of straight male bonding... talking about cheating on your girlfriend/wife. Fortunately though, my friend had the common sense to say, "What about your fiancee?"

Investment Banker shrugged and said, "If a tree falls in the woods, does anyone here it? If I sleep with a whore and no one ever finds out, did I really cheat?"

I have been rolling this around in my head now for two weeks. And I'm not trying to figure out if its cheating because of course it is. What I'm trying to figure out is why this guy thought it was acceptable/cool/funny to talk about disrespecting the person he is about to marry.

Part of the conundrum for me is the gay straight difference. My guess is that the infidelity joke has probably been told a million times between beer-drinking buddies and that straight guys don't actually believe that anyone will do it. Its just a bullshit conversation that guys use to bond. If this is true though, then they must recognize a subtlety that I was not able to pick up, because he sounded serious to me.

I feel like its not cool for the gays to talk about premeditated cheating. Is that right? Do we sit around sipping our carb-free vodka & sodas and talk about how to cheat on our boyfriends without getting caught? (Yes, first you have to go through the trouble of finding friends in monogamous relationships to even fathom that conversation, but had you found those friends, I just don't feel like they would brag about their intent to cheat.)

That said, I think it is important to recognize that I am not placing judgement on those who cheat (unless you do it to me and then fuuuuuuuccccckkkk you). Like it or not, it happens a lot, and if I gave up every friend who ever cheated I would get lonely really quickly. I wouldn't discourage a friend from telling me about cheating, because people make mistakes. But most people make those mistakes spontaneously. Don't they? So to bring it back to Investment Banker, I guess it was his INTENT that really suprised me.

Investment Banker left us after round 3 to go meet other friends. I heard the story of the rest of his night later and it sounded like it ended with some greasy indian food instead of a hooker. So he probably was just talking shit. I guess he should be careful who he talks about these things to though, because blogs make trees falling in the woods much more audible.