Whatever the stark truth may be behind the dramatic split between Tessa Jowell, the Secretary of State for Culture, and her high-finance-flying husband, people will believe the worst. And the worst in parliamentary circles can be very murky indeed. We got some insight into the reality of tension behind the brave smiles when David Mills careered his car into a reporter's vehicle days ago while trying to escape milling predatory press.

Has Mr Mills been a gallant knight, reinforcing his lady's protestations of innocence by distancing himself and his convoluted finances from the threat to her Cabinet career? Believe that if you will. To me, whose marriage ended equally brutally in 1997 when my then husband (Robin Cook, foreign secretary) took a phone call from Alastair Campbell, advising "clarity in news reporting", it is tempting to speculate whether the hand of history has been meddling here too. The circumstances are uncannily similar, though the issue then was sexual rather than any alleged financial irregularity.

The crux of the matter from the Government's point of view was that the Big White Chief should not be embarrassed. Nor should he be seen to meddle personally in a colleague's marriage.

My husband needed no clarifying of the language of spin. As he saw it, the only choice he had, and he made it instantaneously, was whether to drop the wife or the mistress. My semi-sympathetic imaginings yesterday morning dwelt on how Tessa was brought to perceive her stark choice: my husband or my career?

She had hoped, one assumes, that the decision by the Cabinet Secretary and the Prime Minister (that she had not breached the Ministerial Code) would be enough to put her in the clear. It has not worked like that. Even in these opulent times, Labour Cabinet ministers are frowned on by their grassroots support when they casually sign such fabulous sums in and out of accounts and mortgages.

In Radio 4'sAny Questions, a show of hands indicated that most of the audience did not consider the matter resolved. And for very good reason. The Prime Minister is hardly a detached arbiter; he does not want another close Cabinet colleague to depart in ignominy. The decision should not be influenced by him in any way. We know from past government embarrassments just how elastic is his conscience. The highest level of probity should be expected from a minister, and the least she must do is be aware of what and where her investments are, including shared ones, to avoid any possible conflicts of interest.

The plea of ignorance does not exonerate a member of the public for tax mishaps or a breach of the law. The fact that she is pressured and hectically busy is no excuse, and the usual tribal claims that she is brilliant at her job should not be weighed in the balance where her wisdom - if not her probity - is in question.

In my personal misfortune in 1997, I was the total innocent, the loyal but abandoned and humiliated wife. David Mills is the casualty in the 2006 story, and his innocence or otherwise will no doubt be decided in the Italian courts. But what may we say of Tessa's willingness to fling him to perdition at such a time? The very time you should stick by your beleaguered spouse is when your loyalty can serve and support him.

The honourable course for her, to government, party and husband, would have been to resign from the Cabinet to avoid further damage, until such time as all the intricacies were resolved. The media storm would have died down and everyone's blushes spared.

However you examine this story, none of the chief players comes out smelling of violets.