It was lust at first sight and love after the third martini. Over a get-to-know-you-dinner I discovered all I needed to know: I had found the Perfect Woman. All the boxes were ticked and the taxi was winding its way to my bedroom when she said: ‘You should know that I’m bisexual.’

She must have seen the frown on my face because she quickly added, ‘But everyone is bisexual.’

‘No. I’m not,’ I said gently.

‘Yes you are,’ she insisted.

‘No, I’m a heterosexual,’ I said through gritted teeth.

‘No, we’re all bisexual,’ she said with muffled exasperation.

There followed an infantile exchange of Yes you are!/No I’m not! that ended when I snapped and shouted: ‘You bloody bisexuals are so arrogant — you think everyone wants to be just like you!’

She bolted from the cab and my life.

It was in 1970s Britain that I first heard this curious claim that we’re all bisexual. Back then decadence was divine, the film Cabaret was on at your local cinema, David Bowie was on your television (Top of the Pops) with his arm around another bloke (guitarist Mick Ronson). Bisexuality was so fashionable that it seemed that everyone I knew was either bisexual or pretending to be. Even David Bowie, we later learned, was faking it.

The glitter and glam of those years has gone — but the bi brigade and their fundamentalist belief that we’re all bisexual is still alive and active. A new generation of bisexual activists is no longer content to be seen as the frivolous and sexually feral offspring of the gay and lesbian movement. They want to be taken seriously, to stop partying and start protesting. The attempt by some bisexuals to acquire victim status seems absurd, no one says a bad word about them. We have gay bashers, but no bi-bashers. Have you ever heard of someone who was denounced for being bi-phobic? Young teenagers never say dismissively: ‘That’s so bi!’ When diver Tom Daley recently announced that he was in a relationship with a man, but was still attracted to women, he got an international round of applause.

So I may as well come out of the closet and confess: I don’t like bisexuals. I’m not talking about confused and troubled teenage boys and girls who live in small northern towns where a passion for both sexes can make life difficult or dangerous. Good luck to them. No, I’m referring to grown-up metropolitan bisexuals, who move in the fashionable end of the arts, academia, media, fashion, film and pop music; those who flaunt their bisexuality as a display of sexual superiority. They think they’re so cool because they’re so sexually liberated. Why, they ask, would you want to restrict yourself to just men or just women? Why not follow your heart instead of getting hung up on gender and labels?

When I reply that I’m exclusively attracted to women, I get the ‘poor you’ look and then the lecture about how heteros like me are trapped in such a rigid and limited range of desire because we’re afraid to admit our repressed longings. Men like me fear coming out as bisexual because, as Patrick McAleenan wrote recently in the Daily Telegraph, ‘male bisexuality is simply hard for many straights to tolerate’. Actually, male heterosexuality is hard for many bisexuals to tolerate.

They don’t believe that there’s such a thing as heterosexuality or homosexuality (much to the irritation of some gay activists). They argue that human sexuality is never fixed — except by the repressions of religion, social conventions etc — but is always fluid. A younger generation of women don’t even bother calling themselves bisexual, they are just ‘sexually fluid’.

The bisexuals I have met over the years have all been of the lifestyle left; they dismiss ‘mindless capitalist consumerism’ — yet their brand of bisexuality offers a kind of sexual consumerism: why have just one choice when you can have two? It celebrates the ethos that the ultimate good is the freedom of choice — never mind what or who you choose. But the ability to be attracted to and love men and women (which is the traditional definition of bisexuality) doesn’t strike me as being any more admirable than being born ambidextrous.

It was Freud who introduced the idea that all human beings are born bisexual — but even those who slip through the net of biology can still end up in the canon of Great Bisexuals. In her study of bisexuality, Angie Bowie (former wife of David) chooses to cite the following as important bisexual historical figures: Sappho, Michelangelo, Oscar Wilde, Charles Laughton — hold on! Aren’t they all gay heroes? Not any more.

Cruise the internet and you can find all sorts of top ten or top 20 lists of Great Bisexuals with figures plundered from the gay canon. I discovered that Niall Ferguson and William Rees-Mogg were both wrong to criticise the economics of John Maynard Keynes on the basis of the great man’s gayness. Keynes has been transferred, like a top footballer, to Team Bisexual. I was also surprised to discover that the essayist Christopher Hitchens is now a celebrated bisexual, just because of a few gay encounters in his student days at Oxford.

The criteria for entry into the bi canon is so slender that anyone can be co-opted for the cause — even the diarist and Holocaust victim Anne Frank. Bisexual activist Junio Russo argues that because Frank was in love with a boy (Peter Van Pels) and sexually interested in a girlfriend of hers, Frank should be considered a bisexual icon — even though Anne Frank was only 14 when she died. Russo rejects the idea that Frank could have been just going through a phase.

But then bisexuals hate the idea that it’s simply a phase they’re going through, something one grows out of. But consider the fact that so many bisexual idols end up returning to the stable, monogamous heterosexual fold. Singer Katy Perry may have boasted in her hit single ‘I Kissed A Girl’, but she actually married Russell Brand: in 2008 Lou Reed decided to stop walking on the wild side and settled down and married artist Laurie Anderson. In interviews, Angelina Jolie used to talk about her sexual attraction to women — and then married Brad Pitt.

Maybe I should have been more patient with Mrs Perfect — who knows, we could have ended up happily married, and heterosexual, by now.