HOW CAN you be sure your boyfriend isn't shagging Claudia Schiffer? As he caresses your curves, is he thinking of her supermodel figure, her luscious lips, her yeah-baby eyes? Because if his mind is elsewhere, then he might as well be, too.

This week, the Italian judicial system decreed that "adultery in the mind" is just as damaging as any illicit action between the sheets/in the stationery cupboard/in that cheap hotel where you pay by the hour.

A woman named only as `Anna from Ravenna' has been granted a divorce from her husband, Angelo, after developing a "passionate obsession" for a bus driver. Their hands might have brushed when he passed her a ticket, but as for sex? Forget it. Nothing more suggestive passed her lips than "a single to Rome, please".

However, Anna dreamed of life in the bus lane - and as a result, the Court of Cassation overturned a previous ruling and decreed that she was to blame for destroying the marriage. The judge decided to set a precedent, and ruled that a "platonic affair" can cause as much unhappiness as a sexual affair.

This is, of course, a victory for common sense. Anna is not the first person to discover that having an imaginary affair can seriously damage your relationship. In fact, this is even the subject of the new film, Eyes Wide Shut, in which Alice/Nicole Kidman, tells her husband Bill/Tom Cruise that she was once tempted to stray. If Alice had actually acted on her impulses, Bill would have had something tangible to discuss, or someone tangible to hit. Instead, Bill was so distraught that he did the only thing you can do in that situation. He gatecrashed a satanic orgy.

We all know the misery that such revelations can cause. How many of us have ended an affair after our lover mistakenly cries Pammy!/Melinda!/their own name at the height of passion? It's really quite devastating and how can you compete with a fantasy figure, whether they're a porn star or a bus driver?

As Hillary Clinton might say, it's hard keeping a dog on the porch, but you haven't got a chance if he's dreaming of better porches elsewhere. In a dog's imagination, a porch is never unwelcoming, never cold, never without a ready supply of dog biscuits. Need I continue with this analogy?

An imaginary affair will go from strength to strength in your lover's thoughts. He will have virtual sex, and it will always be amazing, and he can even do it in your bed with her. At least you know where you are with a quick how's-yer-father on the office photocopier. And a genetic quirk will ensure that he forgets the woman's name the minute he's zipped up his flies.



HELLO. MY NAME is Annalisa and I am an adulteress. At least a dozen times over, and that's just this year. Sometimes I commit adultery on the bus, or at work, sometimes in Sainsbury's, or when I'm fishing. Or driving, or in an art gallery. There's really no knowing when or where I might do it. Well according to Italy's highest court of appeal, The Court of Cassation, I am an adulteress. You too probably, because this week they ruled that just thinking about being unfaithful is as bad as actually doing it.

This is, of course, utter rubbish. Thinking naughty thoughts about someone other than your partner is most certainly not as bad as doing it. Just as much as thinking about murdering someone is not as bad as actually killing them. (Otherwise I would have been in prison too long ago to be able to commit the adultery.)

Monogamy is not a natural state for humans. Sad, I know. I too want to think that once found, your perfect partner will satisfy all your needs for ever, but it just ain't true. It was once, when women had no choice, but not anymore.

So having crushes on someone and the inevitable lusty thoughts that go with that is good, because it allows us to live out what we'd like to do, without actually doing it. No one need get hurt and no one need really know about these private thoughts (apart from your best friend, your work colleagues and the person next to you in the queue for the night bus).

I strongly believe that mental infidelity keeps relationships going. How lovely to be able to imagine kissing, touching, sleeping with Someone Else. These thoughts can make you feel alive and buzzy without doing any harm whatsoever, because they are not about real life and have no place in it. That's why they exist. You don't have fantasies about going shopping with these folk do you? Nor imagine arguing about where to spend Christmas. These virtual lovers have one role only, but nevertheless it is a very important one: to indulge your private self.

I love my partner more than just about anyone in the world, but he is certainly not the only man in my head and neither should he be. And I wouldn't want to be the only woman in his head either. If, in some hideous mind-controlling future, I could be "caught out" by having these thoughts then I think I'd lose the will to live. I don't think "real" adultery is right, but I don't think it's that avoidable either. If you only get as far as thinking about it, I think you're doing pretty well.

It's no coincidence that this happened in Italy and I could stake my pasta machine that the judge responsible for this ridiculous ruling was a man. Italian women are not meant to be adulterous, in either thought or deed, because Italian men really should be enough for them.

The woman in this case, "Anna", was probably going bonkers with boredom and fancied a bit of light relief in the shape of some steamy day-dreaming. Her only real crime, like real adultery, is that she told someone. In both cases one should keep one's mouth very firmly shut. The great irony of it is that her husband was probably too busy shagging someone else to think about being unfaithful.