Earlier quoted context omitted.
Always interesting to see what other people think is 'cool'. I love my wife too much to swing. Couldn't and don't want to imagine someone else having sex with my wife.
That's because you (and me too) equate sex with intimacy (in the emotional sense). This is not true for all people and I don't judge.
Anecdote - one of my ex was talked into a threesome with another girl by her ex, thinking how refreshing it would be (and she is not a typical nice girl with a good heart to start with). She couldn't handle it at all, and it contributed to their breakup quite effectively.
Nothing for me, I prefer quality rather than quantity (maybe not the best comparison, but I lack better in this case).