Two years ago, this was my life: I worked in a converted warehouse in Hoxton, east London. It was a bright, young company; the work was brain-achingly demanding and we put in long hours. There were often drinks after work. Weekends consisted of hungover mornings in bed and longer alcohol-sodden lunches with friends. Resolutions to take more exercise and see more of the insides of theatres/museums were daily broken.

Yesterday, at 5.30am, I was to be found swaying to and fro in the dark, attempting to coax my toddler son back into his cot for another hour's sleep. His cries of "sha" (lights) and "poi" (porridge) were a bad omen and I soon conceded. On came the lights and we made our weary way downstairs. Some four hours later, after making porridge and changing two nappies and reading a dozen or so tractor-related pieces of toddler literature, I was at baby group. There I talked to a group of mothers about the spate of bird-flu-style viruses sweeping the nation's children while Jack swapped bird-flu-style viruses with their kids. By midday we were home, fed and Jack was unconscious in his buggy. It was my first proper break of the day - I washed up, cleaned and then made a stew for tea. In the afternoon I pushed Jack, a spade and a fork round to the allotment in the wheelbarrow; after a short amount of digging he got bored and we went to the swings. At 7pm, after almost 14 hours on the go, Jack went to bed. I washed up, cleaned up, watched telly with a can of beer, then went to bed early. This is my life.

Last week, a report found that there are now in the region of 200,000 "househusbands" in this country: I am one of them. Like blue whales, we rarely meet and when we do, we cluster. I know about eight other househusbands, although, to be pedantic about it, most of them are part-timers, splitting the domestic stuff with their partners. And part-time is not full-time; there is a profound difference. I don't work part-time or freelance from home. I have abandoned my career to raise our son and, perhaps one day, his sibling. I fully intend to work outside the home again, but there will be no option of going back to what I did before - it wasn't that kind of a career. When I fill in forms now, under occupation I write "househusband".

This wasn't the original plan. The original plan, I think, was for us to have a gap year - a year off together with the new baby, me not working, my girlfriend on maternity leave. But by the end of the year, the plan had evolved. We'd greenshifted and downsized during that year off (ie moved to the country and spent all our savings) and we'd become quite used to being poor and having nothing worse to worry about than dog shit on the village green. There was also the fact that our son had been premature and we'd spent three months of that first year hanging around a hospital; we weren't ready to hand him over to a third party. So it was decided that my girlfriend would work four days a week, and I'd work none. Well, apart from all the domestic stuff.

And so Jack gets me. A lot of his mother too, but a lot more of me. I suspect the overall package I offer him is of the same quality, but more physical and more outdoorsy than he'd get with his mother. A great deal of time is spent in the garden; me gardening, him moving stones from one place to another, or eating soil. When it rains we make indoor slides from table tops. We laugh and roll and rough each other up. We cook together and go hunting for tractors and diggers. He rides everywhere on my shoulders; a proper little emperor.

It is difficult, being a househusband; certainly more difficult than I had imagined. The practical aspects of parenting - naps, meals, baths, bedtimes - are well established. So are the basics of keeping house. None of it is the least bit difficult, once you know how. But a lot of it is boring. And the hours ... they start when it's dark and cold, and they last for an unreasonable amount of time. There is little time to yourself; no time for mulling over your emails, or surfing the web, or popping out for some pleasure shopping. There's no breakfast and a shower before work. You live and sleep on the shop floor.

I realise that the complaints I have are the complaints of a billion housewives since women started keeping cave; looking after children and a home is low-status, poorly rewarded and self-esteem sapping. It's also hard to do well. It turns out that being a househusband is very much like being a housewife - what sex you are makes very little difference.

Of course there are short periods when Jack entertains himself with pots or pans, or in his sandpit. But these periods cannot be relied upon, or scheduled round. The actual work of househusbanding may only take five hours a day but those five hours are smeared across the 13 hours that Jack is awake in a wholly unpredictable manner. Worse still, the job never really ends. Even when my girlfriend is home, I'm still at the coalface, still changing half the nappies and cooking half the meals, and still very much with Jack. Weekends are like weekdays, but with help and adult company. There are no Friday nights in the pub with the sense of another week completed and a job well done. It is relentless.

Then there's the bonus scheme: there just ain't one. A career offers tangible opportunities for progress, defined by increased cash and kudos. Keeping your child physically and emotionally healthy and your home a nice place to live takes an enormous amount of physical and emotional work. Yet it is the minimum expected from you. It is difficult to excel. You're never going to be told by your boss or a member of your team that you're good at your job. Nobody will ask your advice. It's never going to be better than it is now.

It is not exactly the same as being a housewife. For starters, the word "housewife" is loaded down with negative associations; "househusband" sounds New Man, experimental, softy-liberal, empowered - ludicrous, maybe, but an act of choice. I suspect that it's a lot easier being a man in a woman's world, than the other way around. But when you tell people you're a househusband, it is very much like telling someone that you are a housewife: there is no follow-up question. What do you do? I'm a househusband. Oh, they say. And that's it, end of conversation. Although I might then get asked what my wife does.

A recent conversation with a full-time-turned-part-time househusband friend of mine flushed out the fact that he felt "demasculinised", as he put it, by the whole thing; leaving the wage-earning role to his wife had left him mildly unsettled. Me, I have no problem with any of that. In fact, I do remember, even at 5.30am, that working in an office involves stresses, strains and uncertainties that I don't miss one bit. That may partly be the erosion of the self-esteem thing, though. After 18 months at home, the thought of going back into the workplace is genuinely scary. My brain feels atrophied. Once upon a time I could be told a phone number and write it down the next day. Nowadays, I have to look up my postcode.

When I do get ground down, when it feels really relentless, I have to be reminded that this is not for ever. Housewives once went from school into marriage and had little hope of doing any interesting work even when their children had left home. I've spent an inordinate amount of time in higher education, and had not one but two careers. I hope at some point to have some sort of third career, and I just about cling on to enough self confidence to find that prospect exciting. When I remember all this, I remember that my househusbanding is a huge privilege. This is the (extended) gap year that I never took; I'm travelling emotionally, if not geographically. I'm learning about myself, developing the patience and sympathy that I never even thought I lacked. Best of all, Jack and I like each other. I'm always pleased to see him. We spend nearly every waking hour together, yet when I'm not with him I miss him. I know what "poi" and "sha" mean. I do get some time off, courtesy of my girlfriend, to go fish or meet friends. Above all, I know in every bone of my body that I will never regret this. I will not lie on my deathbed and think, oh, how I wish I'd spent less time with my son.