I'd rather be a mistress

Love - and possibly a touch of naivety - is definitely in the smog hanging over Los Angeles at the moment. Jennifer Lopez and Drew Barrymore are no doubt hoping it will be a case of third time lucky when they both remarry later this year. But, given their track records, shouldn't they be more wary of weddings? It's not that I'm an enemy of marriage. In fact, having tried it twice, at one point I probably would have qualified as an enthusiast. It's just that now, at the age of 26, I'm much more a fan of adultery. Indeed, perhaps the best thing about marriage is that it makes illicit sex a possibility.

I married for the first time at the age of 19, in a hippy commune in Florida. I'd met a gorgeous Frenchman while on my gap year, and in the giddy rush of first love we exchanged vows at sunset (I wore a denim bikini).

We honeymooned in Guatemala, wondered how I would break it to my mother, and then decided, three months later, that it would be a good idea to divorce so that I could go to university. Over the next few years I acquired fiancès with careless abandon, but they all proved short-lived.

My second marriage, at 23, was meant to be the big, heartbreaking, till-death-douspart one. This time I had just graduated from Oxford, was feeling lost at the end of my studies and knew how easy it was to get married.

He was a 33-year- old American advertising executive. We met at a party in London and married 12 months later in a museum in Paris. I wore the palest gold Vera Wang silk dress, we danced all night at the Ritz, honeymooned in Venice, and settled down in Milan to what I thought would be domestic bliss. But I had no work, didn't speak Italian very well and found myself becoming an increasingly neurotic housewife.

While my friends in London were spending drunken nights with unsuitable men in rented flats, I was cooking elaborate suppers in my immaculate apartment and buying garden plants. I was bored, unhappy and frustrated.

My husband needed someone who was gentle and restful - not someone who complained about being unfulfilled, laughed at his work and made him feel small because he hadn't read much.

I knew I had to go, and two years later I found myself filing for divorce again. There was nothing particularly wrong with either of my husbands, but sometimes it felt like everything about marriage - and especially the sex - was just another domestic chore. Pay gas bill, buy pak choi, shag husband, take cat to vet. With hindsight, I'm pleased I got out when I did.

With two doomed marriages behind me, I vowed never to do it again - a fairly radical departure from my traditional family background. My younger sister and I had an idyllic childhood in Cheshire, while my father worked as a lecturer and my mother as a teacher.

I left Milan and spent three months sleeping on my best friend's floor in London, wondering how to face all those people who still smiled so hopefully from my wedding photographs.

The worst came when I foolishly ended up in bed with a friend, who commented that I wasn't the type of girl to take home to meet mother: "Two husbands at your age? I don't think so." Since I was broke, I started writing a book about Louis XIV's mistress, and was lucky enough to find an agent.

I rented a flat in Marble Arch and moved on - determined not to let history repeat itself.

So what better than to have an affair with someone who couldn't marry me? My new lover had been with his wife, a beautiful and successful business-woman, for 10 years, and it was clear from the start that he had every intention of staying with her.

He told me that as we snogged furiously in the cloakroom at a party about five minutes after we met. I said that suited me fine. And it did - I found the idea of being someone's mistress quite liberating.

While morals have always been the preserve of the wife, it's the bad girls who get the glamour. After all, Nell Gwyn, Helen of Troy and Christine Keeler are still household names, but who can remember the wives they supplanted?

Mistresses have changed the face of nations and brought down governments - often while wearing some really good outfits. Adultery and luxury go hand in backless Damaris knickers, and I enjoy the indulgent consumerism of being a mistress tremendously. Proper relationships are for joint excursions to Sainsbury's; adultery is for licking crëme de marrons off your lover in a hotel suite when he's meant to be at a conference in Basingstoke.

As the affair with my party snog developed, I soon learned that adultery, like marriage, has its own rules. I was delighted to realise that time-consuming love letters and phone calls were out of bounds, and I couldn't spend my money buying my lover any presents. In fact the only thing I bought him was a bottle of his wife's favourite scent, which I left in my bedroom for him to apply to his shirt before he left - I still think of him whenever I smell Allure. I knew that I was meant to spend my birthday sobbing by the phone, but instead I went out to dinner in my new Prada coat with my friends and didn't feel at all teary.

In fact, my adulterous relationship meant I had space not only for my work and social life, but time to learn about my own needs and expectations. It might seem selfish, but outside the bedroom, I felt no responsibility for my lover's happiness, or his problems, and it was wonderful.

Avoiding emotional intimacy can be very relaxing, and it's something women find difficult to do. I didn't care if he loved me, or found my opinions interesting - I just wanted someone to have fun with. Although being a mistress enabled me to exaggerate my femininity - I had the time to make sure I was always perfectly groomed - it also allowed me to glimpse what it is like to be a man, and it was an education.

Of course, I couldn't help feeling curious about his wife. I promised myself that I would never ask about her, but I couldn't help imagining them together.

He was gallant enough not to pretend that he and his wife had problems, or that they weren't sleeping together, and he never criticised her. I didn't feel guilty, especially since he didn't have any children. After all, as mistress and wife we had two totally different relationships with our man - he loved her, but he wanted to make love to me.

Since I was modern enough to believe that I should share the burden of our grand-hotel habit, it was fortunate for my bank balance that the affair died out when my lover moved to a different country.

I'm sure some mistresses do spend lonely nights crying over a bottle of wine, but for me, I can honestly say there were no drawbacks. If I had the chance, I would definitely become a mistress again. While I wouldn't demean the pain of those who discover their partner is a love rat, properly handled infidelity can be a joyous thing. Being a mistress is a quiet and neglected art, and deserves a champion.

Athenais: The Real Queen of France by Lisa Hilton (£17.99, Little Brown) is out now.