I have to agree with NK... You are stirring.
Please do read some of the threads on this forum... there are many on here who are happily married with extra partners... you have asked the question - listen to the answers.
why not do some research yourself instead of expecting others to explain themselves to you?
I would point you in the direction of Redpeppers journey and TruckerPete's blog... there are many others but they come to mind right now.
Smile! It makes people wonder what you've been up to
Engaged to my sweetheart, WaterWolf