There is an arguable point that if the presence of the second person is a part of the impetus to orgasm, then you're a lot further down the road of intimacy than if he is merely an unconnected fellow-masturbator.

Aqua is correct in saying that there is no blanket definition of cheating, as the "rules of engagement" for every relationship differ.

Basically, if your partner thinks that the act constitutes cheating, you're fucked.

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