A very good article Vag and I can attest more than most (in my third Marriage), that this type of arrangement makes for the happiest. We are also seeing mostly 30's-40's married couples when we hit the swing club, and would love to find one for 50+. I think that the tide with Social Conservatives is changing as well, in that there are now Christian Swingers groups.
Our rules are very simple. We can have what we want, as long we tell the other up front. We met a couple that the husband was kind of a dick to my Wife, and is now taking other Women out (saw him with others at the club a few times), but his Wife was adorable and we had great chemistry in bed. I have shared with my Wife, that I would love to play with Sonja again, and she said to go for it. She also knows of my Asian proclivity and indulges it from time to time. She loves Military men, and I want to give her that sometime. This is the only way to go. I have never loved a Woman so completely as I have loved this one. The things that we argue about, are issues that I never thought would be my worst problem in a Marriage.