There's a guy on another forum I use who is a 'proud' swinger along with his wife, they swear by it and do it very often and make no shame in letting people know!
I must admit, it sounds good from a guy's point of view if in a marriage or a long term R.ship (sleeping with the same woman for the rest of my life doesn't appeal to ME personally) but I'd probably go mental/not like the fact that some other guy is podgering my wife, even if I was doing his! - call me a hypocrit but hey lol.
Why do you ask?