Great lovers: A celebration of true romance

Be your Valentine? I don't think so. Inviting someone to be your love object - as millions of us will do tonight and tomorrow, with slushy cards, chocolate hearts, limp flowers, insipid poetry and themed restaurant dinners - is like inviting them into a lion's cage.

It's asking them to lose themselves in a willed hallucination, a shared dream, a folie a deux, to swim deeper and deeper in an ocean of emotion, to risk everything for another human being and take the chance of losing half your life when it all goes wrong.

True-life love stories, unlike their fictional counterparts, aren't for wimps. You're liable to wind up murdered (like Joe Orton), castrated (Abelard), exiled (Ingrid Bergman), alcoholic (Spencer Tracy), mad as a snake (Lady Caroline Lamb), alcoholic andmad as a snake (Zelda Fitzgerald), knackered by childbirth (John Donne's wife, Anne More, mother of 12 children), chronically unfulfilled (Dante), serially betrayed (Frida Kahlo), or with your head in a gas oven (Sylvia Plath). Falling in love: it's a dangerous game.

It is also, of course, the most wonderful thing in the world when it works out, when it's done properly, when the participating humans are stable and unselfish enough to steer it through storms and squalls into a safe haven. But such success is rare. "What else is love," asked Nietzsche, "but understanding and rejoicing in the fact that another person lives, acts and experiences otherwise than we do?" The short answer is, of course, "everything" - most love stories are about anything but understanding, rejoicing etc the otherness of one's significant other. To appreciate one's partner, rather than seek to control, bully or exploit him/her, is an ideal. Many love affairs have been launched on such idealistic delight, only to founder on rocks of jealousy or betrayal.

That doesn't, of course, stop them being love stories. In hindsight we can see how many troubled and tempestuous relationships were fuelled by a passion beyond reason. That's why we marvel at them: at Scottie and Zelda Fitzgerald, ritzing it up on the French Riviera in the 1920s, with Zelda flinging herself off balconies in jealous rages; at Charles Grey, an MP at 24, hurling himself at Georgiana Cavendish, six years his senior and the grandest of political hostesses, and refusing to be dissuaded. These are timeless stories in their revelations of human character, in their charting of how a mere feeling - something numinous and emotional called "love" - grew to take over two lives. Even the dwindling of passion can make us swoon, as though we were listening to the close of a symphony.

The best love stories are, first and foremost, good stories, full of victories, reversals and droll incidents. Happy marriages, by contrast, may be admirable but they are often a little colourless. Happiness, as they say, writes white. We are delighted that Paul Newman and Joanne Woodward were happily married for decades in Hollywood - but it doesn't make much of a story, does it?

Education and inspiration seem to be at the heart of the greatest love affairs. The seen-it-all philosopher or artist who takes on a new female pupil, starts to teach her the rudiments of thought or creativity, finds himself gazing at her shining eyes and surging bosom, and discovers a new spring in his own creative step - how we love that well-worn story. How we love the idea of Rodin and his student/model/muse Camille Claudel, embedded together in his workshop, falling in love while she posed as his ideal woman and he chiselled out representations of her, to be gazed at for eternity. They were lovers for only eight years, but in our hindsight imaginings, they were together for a century.

Like the other great love stories featured in this two-day celebration of true romance, they move us deeply, and ask us to measure our own loves against them. And, the more we consider the famous passions of the past (and present), the more they amaze us by their multiplicity. The lovers are so different, so peculiar, so startling. What brought the gay economist Maynard Keynes and the impetuous Russian ballerina Lydia Lopokova into a happy communion? What drew the reclusive Elizabeth Barrett to the exuberant Robert Browning? It's too simple to say that opposites attract. So, apparently, do virtual clones, such as Voltaire and Emilie du Chatelet, who worked all day together, discussing intellectual cruxes, then went and read each other's manuscripts, leaving little comments in the margins.

We'll never know for certain what drew these lovers together, or how they negotiated their love through squally periods. We cannot quantify or calibrate love. We can't give these affairs and marriages marks out of 10. We can only stand in amazement at the power of love to magnetise, to ennoble and to blow apart some of the strongest, cleverest and sanest people in history, leaving us to read about them and feel relieved that our lives and loves are, by contrast, thank God, so ordinary.