Awhislyle, I don't think that anyone is saying that it is cheating outright. Just that it is a highly organized cheating fantasy. Think about what that means.

Relationships are a voluntary joining of trusts. It is a mental union. There really are no physical chains or attachments that link two people.

Since it is a union that is highly dependent on the mind, what does it mean to use the same mind to create a virtual environment, within that mind, where you betray the trust that you accepted with again the same mind?

It's dishonest to the self. You're just asking for trouble with that kind of disharmony. Nevermind, for the moment, a dishonesty to your mate.