If you've never worked in an environment where cheating was common, you're lucky. I'm really surprised so many don't appear to find it as common as I've experience in my professional & personal life. I'm not saying anyone here has a SO that would cheat nor am I saying you're wrong for feeling that way. I don't know any of your spouses/fiances/etc., but I personally wouldn't put it past anyone, if the stars aligned.
That's flipping INTENSE @tarheelmjfan! I might have a different opinion if I'd had that experience.