When I had my kids, I bought ipecac syrup to keep in the medicine cabinet on the off chance that one of them might swallow something potentially fatal. Twenty years later, the bottle's still there, its seal unbroken, my heart full of thanks.

We hope for the best, but prepare for the worst. Like any halfway intelligent person, we pay our insurance premiums, get our mammograms, fasten our seat belts, and go through life.

So what is it about a prenuptial agreement that sends the perfectly rational among us into a giant, collective cringe?

The evidence for their usefulness, accrued in countless lawyerly tomes and how-tos since the 1980s, is overwhelming.

We know that, in the U.S., half of all marriages will end in divorce. We know that none of those newlywed couples beaming with promise from the wedding pages dream a split is in their future. We know that when things go awry in an intimate relationship, they can go from harrowing to hideous, overnight. And we know that under the cold, steely gaze of the law, fairness can be reduced to a fairy tale.

And yet, when one person in the relationship brings up the notion of a prenuptial agreement, it's like, well, offering up a shot of ipecac even though there's no poison in sight.

"You find yourself wondering, 'Well, if we're talking about a prenup, then why are we getting married?'" says one newly engaged woman, who has had a few tense conversations with her fiancé about the subject. "If you're looking for an escape hatch, then let's not do it."

"It's a very, very heated and difficult issue for most people," agrees relationship therapist Janis Altman, who, in her three decades of practice in New York, has seen engagements broken over prenups. "Though it really is about finances, it's riddled with emotion. People think, 'Oh my God, doesn't he trust me? Doesn't he love me? Does he think we're going to get divorced?' Some look at it as a paper filled with doom and gloom."

Doom and gloom is right. Statistics be damned; why plan for the end if you're determined it's never, ever going to happen to you?

As a recent headline in Psychology Today asks: "Is it possible that a prenup, while pretending to be your ally, can actually 'sow the seeds' of divorce?" If that's not enough to drive even the most optimistic among us to a box of chocolates and a sad movie, not to mention a really bad date with our favorite person, I don't know what is. How in the world can something be so right, but feel so wrong?

Nuptials are supposed to be some kind of bacchanalian lovefest of food, dancing, fabulous formalwear, and socially sanctioned sex. Anything "pre" that seems like it should at least involve fresh flowers and a punch bowl.

But a prenuptial agreement is a dry, signed, and preferably notarized sheaf of papers prepared by attorneys for a few thousand dollars, a document whose popularity, some lawyers say, has doubled in the last five years. A stack of what-ifs whose creation and discussion, as certified family-law specialist Bob Nachshin will tell you, has made grown men cry as they sit in their attorneys' offices.