One of my writing buddies wrote a fabulous ebook she sent to me to explain the Swingers lifestyle...but it doesn't seem to be on Amazon, so I can't recommend it to you. But there seems to be a lot of guides to look at if you're interested.
Swinging is when you are a couple, yet you participate in sex with other people - which can be swapping partners, sharing partners, sharing one or other of the pair, people watching others having sex, all sorts of forms and combinations! And it's not just a one-off thing, this is a lifestyle choice.
The thing that I didn't understand about swinging, which my buddy so beautifully described and sorted out for me, was the jealousy aspect. How do you not compare/be concerned about comparisons/get jealous about the sharing?
Her explanation was that you loved to see your partner experience sex. So it wasn't all about you. It was about you as a couple.
She said it was important that as a couple you were completely open, honest and communicated well through every aspect of this experience. So when your partner is having sex with another women, you might need him to focus on you, so catch your gaze, stare at you, say your name, and that had to be respected by him and done.
It may be that you feel kissing is too intimate an act to share outside of your couple, so then there is a mutual discussion where you both are happy to reach and agreement, and kissing might be 'banned' from the swinging sex. Or maybe you can kiss, but not French kissing/tongue involvement or whatever it is you agree on.
Swinging isn't about cheating on your partner, or getting some different sex. It's about enjoying your partner's experience of sex, and sometimes that might not be with you. But afterwards, you hear all about it, relive it, talk about it, re-enact it, enjoy the pleasure afterwards in whatever way you both enjoy.
And if I think about it that way...it makes a lot of sense. It'd sure make an interesting story :)