When I was 28, an Australian living in late Sixties London, I launched into a marriage that brought me, along with early episodes of great delight and even a small ration of enlightenment, the most extreme and durable misery I had ever felt.

Her name was Danne: Danne Patricia Emerson. For a long time I believed I could not possibly exist without her; that there was no other woman on earth who could offer me the same sexual and emotional intensity. Erratically and episodically, she cherished the same fantasy about me.

And it was just that: a mutual fantasy. If there was ever a misalliance between two emotionally hypercharged and wolfishly immature people, it was our marriage. I was as unsuited to her as she was to me. The result was a disaster so complete that even now, 40 years and two marriages later, I shudder inwardly when I think about it, though I can’t and wouldn’t deny that we had some good times together — at first.

We met at a drinks party in Notting Hill. “Do you want to meet the best fuck in London?” the host delicately inquired. And he pointed to a sofa, on which sat a tall, rangy, square-jawed blonde holding a glass of warm vodka. We were introduced. Things began to click, small cogs and then larger ones to engage.

Her upbringing had been Catholic; perhaps not as strictly Catholic as mine, but orthodox all the same. Like me she had studied at Sydney University. She had seen me in university revues, seen my writings and cartoons in Honi Soit, the university newspaper, and even seen me briefly on British TV — BBC2.

She had just got to London with no particular plans. But she hadn’t come all this way to do secretarial work in some fucking dentist’s office. She hoped to make it to Italy before long.

Two weeks later we were off to Venice. And less than a month after that she had moved with her few belongings into my flat in Cornwall Gardens, SW7: a neat little two-bedroomer, looking out onto a square of winter-bare trees.

Except to pick up groceries and the mail, and occasionally to take in a movie or a play, neither of us stirred outside much for the first couple of months of 1967. We were both in a feverish and untiring rut, a sort of erotic trance: the first thing I bought for the flat was a king-size bed.

I also made a big mistake. In the course of some conversation about life, liberty and the pursuit of happiness, I remarked that I thought there was no point in getting married unless you meant to have children. Me and my big mouth. A few weeks later Danne announced that her period was late. By February it was clear that she was pregnant.

I had, as far as I knew, only once made a woman pregnant before, and with deep tremors of guilt I had paid for the abortion; but this one we were definitely going to go through with. I felt quite irrationally pleased with myself, as though I had actually achieved something. And Danne, once she was sure that I wanted her to have the child, was thrilled. The hard edges, the scepticism, appeared to be gone.

She was becoming, to my astonishment, a sentimental mother-to-be. Since all fears of pregnancy were now settled, we made love with even more hunger and abandon than before, and in places I had sometimes thought of but never tried, most of them downright uncomfortable: the last row of a cinema, the back seat of a taxi.

I had never, in any real sense, been responsible for anyone else before. Wasn’t I too young to get married? Of course not, I told myself; I was 28, the same age as my brother Tom had been. (This first marriage of his had clearly failed by then, but Danne’s and mine, I told myself, hadn’t and couldn’t.) Now I could be a real man like Tom.

Our baby, a robust boy, was born on September 30, 1967, four months after our wedding. Having rejected orthodox names, we decided on Danton after the French revolutionary. Danne had not heard of Danton before (she had never been strong on history, and a politician had to be black and armed with an AK-47, not a mere 18th-century whitey, to really engage her respectful interest).