My wife cuckolded me a little more than a year ago...actually its closer to two years now. He happened to be our neighbor (at the time) and he became a best friend to both of us and still is. It was very convenient that he happened to live next door so she could go over in the middle of the night, fuck him, and come home freshly fucked for me. I never did get to see them fuck, I saw him kiss her though.
As to jealousy...I only experienced that one time. A large group of us 30+ went out on a bus trip, bar hopping for new years. When the bus dropped us off at my house, she had planned on teasing him and fucking him first, instead of me to bring in the new year. She asked if I minded if she could just stay overnight...of course I said she could, but that night is the first night I experienced jealousy...she fucked him first for the year, and fell asleep in his bed and arms. Coincidentally, she also fucked him that morning, and went back to his house around noon to collect some clothing she forgot (wink, wink), and fucked him again.
Oh how I miss my wife being naughty.