Reading the posts here, I thought about the paradox of affairs and communication in the electronic era. Cell phones, burner phones, email, text ing, ims , and the like make clandestine communication much easier than it was in the days of mail and land line only communication.. The velocity of communication has exponentially increased. You can set up a quickie in seconds.
Yet, most of these are traceable as Guiness23 says. If, and only if, the betrayed spouse thinks to check. Not to mention the universally-present cameras and video recorders on cell phones. Eyes are everywhere.
In balance, you'd have to be nuts to think you'd be undiscovered forever. Cheating may be easier these days, but you better be looking everywhere at all times when with OP.