OK, I get it. I would love that. I want to start small and work my way up. (Instead of "small" I should have said simple)
I've suggested to a few guys on this site to stop shooting for the moon. They should take baby steps to try to get this going. Don't just ask your wife to fuck other guys, maybe start with some flashing. You could get braver and braver. Then after that you could create a situation where someone saw you having sex with your hubby.
I think the next great step would be for the wife to get a massage by another guy. (now the touching has began)
Next would be a discreet hand job with a stranger. If she's OK with that, you'll have her fucking other guys in no time.
So I like the challenge idea, but I would like to start small/simple.