Good advice, but isn't that in a way giving the cheating spouse permission to continue the affair, and sending a message that you're willing to tolerate the affair?
No. This should be your response to anything LEGAL, or when they try to engage you in a detailed R convo. Your position of "What you're doing is destructive to our family, and I WILL not live in an open marriage" should be repeated often, and never wavered from.
