david petraeus paula broadwell planeCSM Marvin L. Hill

In the wake of the shocking resignation of one of America's greatest generals over an extramarital affair, the recriminations have begun.

Predictably, many people, including a Petraeus colleague, are already "blaming the woman." A nobody graduate student charms her way into the confidence of a powerful man — and then uses her seductive powers to bring him down.

Petraeus himself, in contrast, has admirably taken full responsibility for his downfall, declaring his behavior "unacceptable" and proactively resigning over it.

Meanwhile, both General Petraeus and Paula Broadwell have spouses and families who have already presumably been seriously wounded by the highly public affair. And the country has lost an extraordinary leader.

So, who's really to blame?

What is the central mistake here that everyone should learn from and try not to make?

The obvious answer is that you shouldn't cheat on your spouse, especially when you're in a position of such power and responsibility. Leaving aside the moral and personal issues involved, this behavior exposes you to enormous career and reputational risk and is therefore reckless and irresponsible.

But that answer is so obvious that it's not really helpful or insightful. Except for those who make extracurricular activity a way of life — the age-old lifestyle of "the mistress and the wife" — most people know that they shouldn't cheat. And yet, time and again, relationships, careers, families, and reputations are wrecked because good people make the same obvious mistake.

(Yes, sometimes, these "mistakes" turn out to be for the best. One or both participants use the affair as the trigger to end an unhappy relationship and then go on to spend their lives together. But too often, the affairs really do prove to be mistakes — mistakes that wreak havoc all around.)

So, what's the real lesson?  Is there a small mistake that often leads to the bigger mistake — a small mistake that is more easily avoided than the bigger one?

I think the answer is "yes."

Many years ago, long before I got married, I asked a happily married friend what her secret was. Specifically, I asked her how, in her second marriage, she had avoided succumbing to a temptation that had helped end her (very early) first marriage and the marriages of many, many other good, responsible people.

Her answer, learned from experience, was simple and quick:

"Never put yourself in a position where you're asking for trouble."

I had never heard that answer before. So I asked for details.

"You don't die when you get married," she explained. "If you spend enough time hanging out alone with someone you're attracted to, nature's eventually going to take over."

Even at the time that answer struck me as wise. And nearly thirty years later, it still seems wise.

We're animals, after all. And one reason our species has been so spectacularly successful over the millennia is that our instincts are powerful enough to trump just about everything — one instinct in particular.

By all accounts, General David Petraeus had more willpower and discipline and sense of professional duty than just about any man alive. If a man like Petraeus can fall prey to the same mistake that has destroyed so many other marriages, careers, and reputations, perhaps it's time we began to look at such mistakes differently, at least when it comes to trying to avoid them.

Specifically, perhaps it's time we acknowledged that, when we allow ourselves to be placed in certain intimate situations, these mistakes are very easy and natural to make. No matter who we are.