"Cheating" is a very narrowly defined cultural concept that the question posed suggests it deserves a great deal of weight word pondering. It's probably the same as asking what's better, being a morman with lots of wives or a catholic that can't use contraceptives. Depending on your upbringing and point of view you care about the question or not.
It is just another facet of being a flexible-thinking human.
One has close relationships with their kids but doesn't have sex with them. Kids love their teachers and singer and TV idols and no one considers that "cheating". Parents don't discuss what mommy and daddy do in the bedroom, and kids don't want to know and they don't get jealous they might get less attention.
Boning a hooker could equate to a quick trip to a nice restaurant. If your wife finds out you had a good meal does she refuse to cook for you again?
If your wife bones your best friend and you snog her brother then you are even, but most people would keep that a secret as it is a social taboo for most people.
The thing is with the secret disposable stuff is you can't really take photos and stick those images up on the wall. So if you are spending a weekend and cash boning a hoe rather than going camping with your wife and kids, one event is a memory for you, the other is a memory for the whole family.
If you keep a fish in an absolutely clear tank with no place to get cover, no plants to hide under and de-stress, they (I'm just guessing here) don't live as long as the fish in an interesting aquarium with plants, hidey spots and murky water.
When your spouse comes home in a fabulous mood, has an extra spring in their step and tries out a new party trick a hooker taught them, maybe both sides benefit. Your courteous spouse paid a hooker to go away, you aren't going to marry them. Explaining away the $300 for an hour of screwing vs not having that cash to make the car payment is an example of the juggling that comes with such decisons. Cheating, gambling, alcoholism, deciding to switch genders mid-marraige, there are all sorts of questions one can pose.
There is no point muddying up the question with innumerable variables such as the variety of 'what-ifs', no-sex, bordom, forced obligations, fear of what might happen and so on, the point is that you get to choose whatever you want to do and manage whatever needs stick-handling to make things work.
