› firstname.lastname@example.org 
I am a happily married man (16 years). My wife and I's lives are pretty good. But I have a recurring fantasy about swapping with a couple who are our friends. We flirt and play around (no touching) but we have skinny-dipped, flashed our parts, etc. What I can't figure out is why I want to do more. Thinking about it turns me on a lot. I have spoken to my wife about it in a general way but never mentioned it to our friends and she typically just laughs. What do you think?
I think you have to go back and change, "My wife and I's sex lives are pretty good" to "My wife and I have a pretty good sex life." Unless you:
A) want people to think you and your wife have two completely separate sex lives and
B) want people to think you're a moron.
If no one else is going to take a stand against pronoun abuse, then by golly, it's going to have to be me. I. Me.
Grammar aside, I don't see what's so terribly confusing about this situation. I assume all of you are semi-youngish, still cuteish and hornyish, and often quite drunkish, or at least that's the picture I'm getting. There's nothing wrong with being any of those things, of course. I do not judge! It turns you on because other naked cuteish drunkish bodies are meant to turn you on, and because while many men in particular (although this is not in any way limited to either the young or the male) may find themselves satisfied day-to-day with who and what they've got at home, they would jump at the chance for some free (that is, wife-approved) alternative nookie. Nobody will be shocked to hear this, I assume? Some fidelity, granted, is fueled by honest-to-God "I only have eyes for you"-ness. But another substantial chunk is inspired by the "I'd like to, but she'd kill me" sentiment. Swapping, presumably, removes imminent murder from the equation, hence its appeal at least in theory.
Since you used the word "swap," I'm assuming that the lure here is the other wife. Of course it is possible that you, Mr. "My wife and I's," do not so much value precision in language and really meant "all get together in a great heaving heap of miscellaneous body parts," in which case it's even less surprising. Nothing like a nice old-fashioned orgy to get those unnamed, unconfessed itches scratched before pretending they never itched in the first place. But whatev. It doesn't matter why you want to do this: you want to, that's all. Too bad you're not going to get to.
What? How do I know? Because, silly rabbit, you have asked your wife (and more than thrice, I suspect), and she just laughed. If she was interested and had been waiting for you to bring it up, she would have laughed, yes! and then gone on to say: "We should ask them (giggle)! I mean, just for a joke! And see what they say, you know, just for laughs (giggle)." She would have said that, and she didn't. And now you have to drop it. You get three tries with most things like this. After that, it turns into pestering or, depending on the dynamic in a given household (no aspersions cast), bullying. There are always exceptions. It is acceptable, for instance, to mention more than three times that you think your partner ought to be getting more of the oral sex. Even that would wear thin pretty quickly, though, if not actually accompanied by more of the aforementioned oral sex.
When it comes to more controversial acts, though, like wife-swapping or bondage or anal play, I think most people say no when they seriously mean no. By the second offer, most people who might be a little or even a lot interested but don't feel comfortable copping to that yet will whisper, "Let me think about it, OK?" And you have to back off and let them. By the third time, they should be ready to say yes or no. What's to be gained by a fourth try, or a fifth?
There are, of course, subjects that can only be brought up once and then they must be banished forever. If you want to raise one of those, you have to bring it up the right way, which goes like this:
"Honey, come watch this video with me."
"What's it about?"
"Um, pooping on people."
If you receive a resounding "EEEEEEEEEW! NO!", you will know to drop it. If you don't drop it, there is no help for you. Compared with pooping on people, your fantasy is pretty tame. But you still only get three tries and then it's back to the "flirting and flashing" for you. Be glad you've got that.
Andrea is home with the kids and going stir-crazy. Write her a letter! Ask her a question! Send her your tedious e-mail forwards! On second thought, don't do that. Just ask her a question.
Andrea is also teaching two classes: "You've Really Got Your Hands Full" a realistic look at having twins at Birthways in Berkeley, and "Is There Sex After Motherhood?" at Day One Center in San Francisco and other venues.