Okay, so the title's a touch misleading. (Yes, he did sleep with the best friend, but no, at the time, he wasn't dating his fiancée.)
A reader writes:
"I met my fiancée in college. We were great friends but she was in a relationship for the first 2 years I knew her. She knew I was interested but she loved the guy at the time. Anyway (this was almost 4 years ago now) she set me up with her best friend just for a night of fun. We got drunk and had sex.
"Well, long story short, she (my fiancée) broke up with her boyfriend and we ended up together. Now, since we've been together that night 4 years ago with her best friend has always caused tension with her even though we frequently hang out with the friend and her current boyfriend.
"The latest is that the best friend is the only possible maid of honor, but that she doesn't want a girl that slept with me on the alter with us (or even in the bridal party!). She admits that she's the one that set us up that night in the first place, but now she is talking about eloping just because of that night. We both want a small but traditional wedding and I'd hate for her to throw it away because of this. How in hell do I handle this one??
We'll admit. That's an odd one. You really did manage to thread a needle--somehow sleeping with her best friend but emerging from the whole experience, ethically, spotless as a lamb. Well played, sir.
It's possible, theoretically, that there's some complex, long-term solution that tackles the root of your problem. Some clearing-of-the-air that will buttress the women's' friendship, slice through all the tension, and pave the way for the wedding of your fiancée's dream.
This is not that solution.
Instead, we propose a compromise that's disarmingly simple: keep your wedding, ditch the bridal parties.
Done and done. No maid of honor, no bridesmaids, no best man, no groomsmen, no anxiety that will poison the whole affair.
Is this ideal? Nope. On a continuum, however, it's closer to your fiancée's original wedding-vision than if you, say, scrapped the whole thing and eloped.
There's precedent for this. Plenty of people have done it (usually, admittedly, not for this exact reason.) Just tell everyone that you want a very "simple ceremony" but you also want your family and friends in attendance. This way you get your traditional wedding without your "original sin" staining the altar.
It should go without saying, of course, that whenever you and your fiancée discuss this issue squarely, you repeat that you have utterly NO ATTRACTION to this woman, that there would never, ever, ever--in any alternate universe, even a universe where both of you were single--there would never be a scenario where you would repeat that one drunken night. You never think of her that way. In fact, it was so long ago (and you were so plastered) that you can't even remember the night. Now you think of her like a sister. The thought of anything else (with this girl) feels gross and creepy and not at all sexy. Yes, she knows all of this, but it will be good to hear you say it.
One more thing to think about. If you decide to elope, it will, paradoxically, give this girl--and what she represents--even more power. She will have torpedoed your wedding. She will loom even larger, as she will have driven every "Big Picture" decision about your wedding's venue and character.
By removing the position of Maid of Honor, you (mostly) sidestep that issue. (We assume she doesn't have a sister, right? If she does, then that's another easy fix.)
Hope this helps. Good luck.