Geez, How Common of Fergie to Split : ROBIN ABCARIAN

It comes as no surprise that the Duchess of York and Prince Andrew are Splitsville.

Those of us who do our most intense information-gathering at supermarket checkout counters have been concerned for months that this royal marriage was in trouble.

Or was it someone else’s royal marriage that was in trouble?

Dear me, it’s getting awfully hard to tell those troubled royal marriages apart. You really do need the tabloids to keep them straight: Diana and Charles? Trotting along in opposite directions. Anne and Mark Phillips? Legally separated; no announced divorce plan s. Margaret and Lord Snowdon? D-I-V-O-R-C-E-D. Leona and Harry? Madly in love, but insa . . . oops, wrong dynasty. In the House of Windsor, divorce is as common as a Mr. Ed smile.

To recap the uncoupling: In May, 1990, while Prince Andrew was at sea with the Royal Navy, Fergie was at play in Morocco with a Texas oil heir named Steve Wyatt. By all means, this was not Fergie’s first transgression; her ever-tackier foibles have been well documented since she and Andrew wed almost six years ago in a Westminster Abbey ceremony televised across most of the solar system.

Apparently, the much-rumored vacation was nearly forgotten until a cleaning lady found 120 snapshots in a London flat that Wyatt had recently vacated. The photos were given to police, but, lucky for us, the tabloids got hold of them too.

One hardly knows which was less discreet: vacationing with an American playboy while married to an English prince, or leaving proof of a ridiculously over-documented vacation where others were sure to find it. Perhaps this pair were meant for each other.

The queen is reported to be in a tizzy over the latest dissolution, although I’m not sure how anyone can tell. How does one detect tizziness in a woman whose visible emotional spectrum runs the gamut from frozen to blank? And yet, one can imagine her pain. Among her many titles, after all, is Defender of the Faith. It must be an awful strain on that faith to see so many vows of holy matrimony a shambles.

Imagine the courage it takes to divorce the Queen of England’s son. You’d think a prince at your elbow and an annual stipend of $450,000--not to mention a horrifyingly Encino-ish mansion to call home--would provide powerful incentive to a duchess not to ditch her duke. But no. A bad marriage, no matter how blue the boy’s blood, is simply not tolerable to a girl with a detectable pulse--a Royal Family phenomenon last observed in the Duke of Windsor.

(Ample, taxpayer-generated alimony is tolerable, however; lawyers are working out the details.)

No official announcement has been made concerning custody arrangements for the couple’s little girls, Princesses Beatrice and Eugenie. They are the first children so near the throne (their father is fourth in the order of succession) to be subject to such a legal entanglement.

Should the marriage of Charles and Diana end, royal watchers have said with certainty that custody would automatically go to Charles because sons William and Henry are second and third in line. Very Corleone-like, I dare say. And, like their cinematic counterparts, the Windsors do not appear to be a forgiving clan. A BBC correspondent was quoted as saying that “the knives are out for Fergie at the palace.”

What could have caused the frisky duchess to stray? Some blame the prince’s parsimoniousness for propelling “Freebie Fergie” (as she is known) straight toward Wyatt’s open wallet.

The real question pondered by those who keep copies of Debrett’s Peerage on their bed stands is whether anyone can really expect a British royal to stay happily married to a commoner.

The problem is insurmountably tautological: Commoners are so bloody common. They expect to be able to act like humans and be treated as such. They want love and glamour. Money and freebies. Titles and vacations abroad with Texans to whom they are not married. Silly ninnies.

Don’t they understand that when you marry into royalty, you simply cannot have it all; you can only have nine-tenths of it?

What, one wonders, will happen if royals henceforth refrain from dipping into the commoner population for mates? Are there enough titled Europeans to go around, gene pool-wise?

Probably not, even if you count the Eastern European pretenders who have emerged like termites from woodwork since communism collapsed. They’re all related anyway.

Anyone who has seen “Deliverance” knows what that means: Their children might be a little on the homely side, but they’d mighty fine at pickin’ a banjo.