America and most of the world clings to sexual monogamy as a moral absolute when in fact it is merely an extreme reflection of one tendency in human nature: the need for most post-adolescent human beings to bond with one other person. But that is a matter of the heart and mind, not the gonads. And there is another tendency in human beings, stronger in men but plenty present in women, to reach out sexually to others.

Failure to accommodate both these tendencies guarantees that either the extreme rule will be broken (resulting in adultery rates of 50% such as we have had for as long as the numbers have been kept) or endless yearning for something more.

Only the "deviants" in our society who support sexual sharing, along a spectrum from hardcore (uncaring) swinging to polyamory (shared hearts as well as genitalia), have reached the place where the heart and the libido are travelling in the same direction.

So I regard all sexual advice which fails to recognize the need for such accommodation as being as futile as alchemy.

But there will always be limits of some kind. How does jealousy fit into the model of sexual sharing? It fits if there is a rational threat to one's primary relationship.

As to ex-lovers, it makes a lot of difference how serious the relationship was. The more casual, the safer it is to allow a resumption.

In the present case, it is helpful that the ex-lovers are numerous. I would dine with all of them and allow, even encourage sex with some of them, if that's what she wants, understanding I would be similarly occupied with their partners as well.

Such a life is not without risk, but experience has shown that if the primary bond is solid, all the other relationships are just friendship of a special kind.

The reasons Lieberman is holding the door open to switching are these: (1) he knows Democrats in his own state are presently hostile to him; and (2) it aggrandizes his power within the party. He envisions a lot of ass-kissing from the Democrats.

But I think White House discipline over Senate Republicans ended with the election, and every moderate Republican will now go his/her way without fear. It's a shambles over there. Expect many of them to vote with Democrats anytime there is something reasonable on the table, and claim credit for getting things done. They desperately need to get some things done, things that appeal to the center and not "the base" (in Arabic, al-Qaeda).

That means that on any issue where there is a moderate consensus, Joe can get on board or go fish.

On no issue will this be more clearly seen than on Iraq.

On Sunday, Lieberman and McCain parked themselves outside the current scope of debate. McCain, painfully evoking Vietnam without naming it, used identical language from those days about never quitting and committing ever more resources to the fight until it is won. Lieberman agreed, using the analogy of World War II, as though we were fighting another nation with an army in the field. They have support among 16% of Americans, according to a poll last week.

So when the bipartisan Iraq Study Group mandated by Congress comes out with an exit strategy fashioned chiefly by Bush Sr.'s boys, there will be a bipartisan rush to embrace it as though it were an object of lust.

And Joe Lieberman will be totally ignored.

So pretty soon he will start talking like the old Democrat he used to be, when his party was in power and he gained nothing by sucking up to the Republicans, because that is where the world is again today. He can have impact again, but he will not be calling any tunes.