I suspect the hidden meaning is that guys apparently cheat on people who are fundamentally no different to the person they’re cheating on.

The implication being that guys cheat for the sake of it, rather than because there’s a difference in the person their with.

For clarity, I’m not saying I believe any of that. I think it sounds like utter nonsense. No doubt it’s true for some people, but I think applying it to a wider group isn’t very reasonable.