The tabloids must feel that Nancy Shevell is the Sarah Palin of girlfriends… someone you’d never heard of, and now, as Paul McCartney’s squeeze, she’s everywhere. But she may be more like a Camilla Parker-Bowles, Prince Charles’s true love, who was introduced only gradually to the public as his girlfriend.

They were first spotted together 10 months ago in the Hamptons and, despite a gazillion pictures of them smooching and holding hands, she said they were “just friends.”

As of last week, and next, the McCartney-Shevell relationship is all out in the open. They made a very public appearance last week at a fashion event in London for McCartney’s daughter, Mary, after which Shevell joined the McCartneys for dinner. His family likes her a lot, he said.

McCartney raved that night about Shevell and their American cross-country trip on Route 66 in his 1989 Ford Bronco: “Brilliant,” he said.

That’s not a trip you take with “just a friend.” They drove from the Hamptons, to Illinois, to Santa Monica, proving that traveling with a former Beatle means the whole world is like a small town full of gossips. Numerous people along the way, including a man who gave them a parking ticket, seemed flummoxed to find Paul McCartney in a vintage Bronco, making a pit stop at a gas station, or checking into a hotel.

The tabloids kept up breathless coverage, and began discussing marriage. (Technicality: she’s still married.)

McCartney put the brakes on those rumors somewhat by saying, “It is still early days, but we are very much together.”

Early or not, they have also vacationed in the Caribbean, and Shevell will go with McCartney to Tel Aviv to watch him perform at Israel’s 60th birthday event on the 25th of this month.

This is not a trip to be taken lightly. A Syrian fundamentalist has announced that McCartney is now “an enemy to all Muslims,” because going to Tel Aviv means he sides with the oppressors.

Shevell, by the way, is Jewish, as was McCartney’s first wife, Linda Eastman, and is said to be all in favor of the trip to Israel.

So who is this mystery American, a ladylike and willowy brunette who has had, like Linda McCartney, breast cancer?

What is known is that Nancy Shevell, 47, is amicably separated from her husband, Bruce A. Blakeman. As of November last year, neither of them has been seen wearing a wedding ring. When Nancy Shevell’s brother died in March, Bruce Blakeman was not mentioned as a survivor, although their son and another brother in law were. She dropped the name “Blakeman” at the end of last year.

Let’s stop right here and say it is not a good idea to start dating during a divorce proceeding.

McCartney was still in the middle of his frantic divorce from Heather Mills last year, and the rumors of a McCartney-Shevell relationship made Mills even more unstable.

Meanwhile the Shevell-Blakeman legal separation and coming divorce have proceeded with no fireworks or drama. There’s a reason they want it to go smoothly.

They have a teenage son, Arlen, who is in school in New York City; Bruce Blakeman, a lawyer, is running for mayor of New York City in 2009; and there is no reason for them to have a contentious divorce, since they both came to the marriage with considerable fortunes, hers from her family’s trucking business.

McCartney, by the way, has a home on Fresh Pond Lane in Amagansett; the Shevell-Blakemans have a home in East Hampton, six miles away. McCartney’s Ford Bronco was seen several times making the six-mile trip and they were snapped sailing off of Amagansett, and eating sushi there.

And many observers have pointed out that, even if McCartney may not be dating a woman his own age, but he’s at least dating a woman closer to his age. (Shevell is 47; Heather Mills is 40.)

Besides traveling around the world with a former Beatle, Shevell seems to have had one clear change of heart. Her soon to be ex-husband is a Republican, and as a couple they backed Republicans and took appointments from Republican Mayor Rudy Giuliani.

Her husband’s appointment has run out, but she has three more years to serve in her (unpaid) position on the board of the Metropolitan Transit Authority.

But a check of campaign contributions shows that Shevell, after a lifetime of supporting the Republican party, donated $2,300 to Barak Obama this year.

It must be love!

So now it’s your turn: Should a woman of 47 grab the possibility of love when it comes along, and give up on a 23 year marriage? What if he’s a former Beatle? What if he’s a former Beatle and he writes love songs to her? Is it fair to her son? Who should be put first?