Mid 50s couple here, been enmfm fun with a guy we know off and on for 5 years. It's become a semi regular thing for us with him.
One other guy once, different guy 3 times, neither were nearly as much fun as our regular friend.
We're very conservative, not stingers at all, we've never gone looking fir fun, it just happened.
Met a couple on a cruise, they were our age, polite, fun to spend time with, we met couples, enjoyed drinks and visiting many times. Was last day of cruise, we were in their cabin enjoying wine on their deck. My wife, and his evidently, likes to sun topless when appropriate. The moderately drunk wives take tops off. No big deal. Girls get to talking, turns out they had done mfm. Wife and her really hit it off swapping experiences. Other hubby and I are like WTF? More wine, soon we're all naked on their balcony. I really don't know how but we were on the bed, his wife kissing my, mine kissing him. Very awkward buy exciting as hell. We end up fucking each other's wife then fucked our own. Both girls really got off with the whole deal. It was fun but I like our mfm fun with our friend.
I will say it was damn hot messing with his wife, different than mine.