When a man marries his mistress he creates a job vacancy. But when a mistress becomes a wife, she doubles her workload, says Maureen Freely
When you marry your mistress, the late Sir James Goldsmith once said, you create a job vacancy. It's a cruel thing to say, but the whole truth is even worse. Ask any woman who has gone from mistress to wife and you'll find out what happens before the man starts scanning the "Positions Wanted" column. There is a long and ghastly honeymoon period when the mistress turned wife has two jobs rolled into one.

It might sound strange to apply a cold and precise word like "job" to the shadowy life of a mistress. After all, very few of us commit adultery with multi-billionaires who set us up in mansions with every comfort and a lifetime supply of china bowls to break over his head. Most of us leave our money sense at home when we venture into adultery, and the same goes for our common sense. We pay our own way as we fool ourselves into thinking that the man in question is married in name only, and only because he has such a fine character and takes his obligations so very seriously. We call it a job and become convinced we are providing an essential service, to enhance the romance and allay our guilt. We look into the mirror and see Sarah Bernhardt - except that she got paid for her hard work, while we are prepared to play the part of selfless female for nothing.

Perhaps other women aren't quite this delusional. I had to be, because so many things I said and did during my time as mistress flew in the face of my own views on equality, social justice and the proper conduct of husbands. I mean, I'd been married myself for 13 years. I'd marched out of it full of unkind accusations about new men who were even worse than the old model they had replaced. I had entered single parenthood determined to live a quiet and dignified life, and then suddenly there I was, rushing home from the school run every other Friday morning to put the wine on ice and add the finishing touches to a lamb and bean stew before dashing upstairs to change into my most wanton underwear.

There was no pretence mixed in with the sympathy I gave my lover during those stolen lunches. How hard it must be, I thought, for a man to be held to a schedule as strict as the one this wife of his insisted on. Where was it written that a man had to be home every evening at six on the dot? That he couldn't go out with his friend for an innocent afternoon at the pub after Sunday tennis? Was always the one who got up with crying babies in the middle of the night, never, ever got a weekend off? You see, she had trapped him into staying married by getting pregnant accidentally not once, but twice. Granted, he now loved the children more than he would ever love her, but why did that mean she couldn't allow him any pleasures?

The least she could do would be to let him listen to dissonant jazz in the evenings without screaming bloody murder until he put on his headphones. I remember how affronted I felt on his behalf when I found out she objected to his buying an expensive new set of speakers for his stereo. Didn't she understand how hard it was for a sensitive man like him to listen to any kind of jazz through cheap, old speakers that popped? She certainly made time for her little pleasures. I had heard all about her late risings, afternoon naps and endless visits to the hairdresser. She didn't know how good she had it. I remember his telling me once about how angry he felt when she went to bed early, leaving him to do the dishes. The vixen, I thought, she even makes him do the dishes.

I'm sure he felt very lucky to have found a woman whose heart was so 19th century, despite its 20th-century veneer. It must have been one of the reasons why he wanted to set up house with me after his divorce. But it was very hard to see things like a mistress when I was also having to depend on him like a wife. I did try to make allowances for his true feelings about dishes, late risings, naps, six o'clock tea times, four o'clock feeds, pubs and weekends off, but every time I did, it meant more dishes and broken nights for me, and no pubs or hairdressers. As for that dissonant jazz, well talk about headaches. My compassion failed utterly when he came home with a new transformer that did justice to those new speakers - without even asking if the money would have been better spent on the carrycots and pushchairs that we so desperately needed.

I suppose I should add that by this point I had surprised us both with not one, but two accidental pregnancies. He never said it, but he must have asked himself if I was turning into his wife. Although I never said it, I sometimes wondered the same thing. The person I live with now is not the free spirit I had the affair with. He abides by the strictest of schedules and the highest of domestic standards, is always picking up after me, can't bear the haphazard way I pile the dishes, has almost given up hope now of ever teaching me how to do them properly. He's also a much better man than I realised - but that's luck. Most mistresses who turn into wives have ruder awakenings. How relieved they must be when that stranger, their husband, starts acting shiftily and slamming the phone down the moment they walk into the room! They have to keep up the pretence of jealousy, of course, but secretly they must be saying, thank God the old windbag's finally filled that vacancy.