I spent two decades slogging my guts out at work. As my responsibilities grew - four kids and counting - so did my earning power. I changed jobs, companies, even countries to further my career. But as the years went by I became aware of an increasingly persistent voice in my head. What's it all for, Nige? Your life is slipping away. I spent the last 10 of those 20 years having daydreams about giving up work.

Then in 2003, I suddenly found myself downsized and living in Sydney. We had left the UK when I was offered a job running the Australian office of a leading advertising agency, and then, a year later, the company closed.

I had just finished reading Manhood by Steve Biddulph, in which he argues every man should be forced to take his 40th year off. His theory was that most men don't have a life - they pretend to have one. In reality they are lonely, emotionally timid, and miserably, compulsively competitive. One of the main reasons they never get out of this tragic state is that they are enslaved by jobs that lead them to put their lives on hold until retirement. Thus, as Biddulph puts it: "Our marriages fail, our kids hate us, we die of stress and on the way, we destroy the world."

His year-off notion struck a chord. And with the closure of my firm, it seemed a good time for a pause for reflection and a change of direction.

Kate and I had been married for 10 years. Along the way, she had given me four gorgeous children. Alex, Harry, and our three-year-old twins, Grace and Eve created a tidal wave of loving welcome every time I came home after work. Increasingly, I was responding to this barrage of love with a grunt.

Work had become far too dominant in my life; I had become a bit player in my family - leaving in the morning before they got up and arriving home after they were in bed. Sometimes I was so spent I would stay in the car listening to the radio rather than going inside. Perhaps a year off was precisely what I, and my family, needed.

I clearly needed a proper discussion with Kate before doing anything rash, so we went out for dinner.

"I want to take a year off," I started.

"To do what?"

"Don't know. Nothing. Not put a tie on. Get to know my kids properly."

"But how would we earn money?" Kate asked.

"We wouldn't," I replied.

"Then how would we live?"

"Off the redundancy payment."

"How long would that last?"

"If we were sensible, it could last for a year," I replied. "We'd have to move to a smaller house. And sell the Subaru. And the nanny would have to go."

"And what would happen at the end of the year?

"We'd be fucked. All our savings would be gone. I'd be a forgotten, 40-year-old advertising executive who hadn't worked for a year. Unemployable."

"So I get twice the husband, half the income and at the end of the year we'll both have to work in Woolworths?"

"Basically."

Kate thought for a minute. "If we do this, will you be less of an arsehole?"

The first day of my freedom didn't feel momentous. I began by signing up for school canteen duty. It was a thrill how delighted my sons were to see me behind the lunch counter.

"Hi Dad, ham pizza," said Alex."Did you know, in Indonesia, rather than using the word 'very' before a word they just repeat the word. Banana milk please. So you would be 'fat fat' not 'very fat'. Cool isn't it."

Parenting wise, over-ambition and general ignorance quickly proved my undoing. I found I didn't know what to do in the simplest of situations. It is one thing being asked to "dress the girls", but quite another knowing what they should wear and where those clothes actually were.

A few weeks into my new life, I was shagged. Completely drained in a way that work never affected me. Work pressure energised me; the relentless domestic grind took my life force, crushed it. Nothing a good night's sleep wouldn't sort, I initially thought, but with four kids under nine, the number of nights when none of them woke up for some reason was currently running at 1:4. Far from having time on my hands, it was a struggle to cut out the space to do anything other than wipe arses or read Pingu.

But as I got further and further away from my office-slave routine, I started to gain glimpses of how a family could exist happily as one. The relentless grind got steadily less exhausting; the school run gradually ceased to be hell. I found I could get enormous amounts of joy out of the simplest of things: Harry standing next to me in the mornings, mimicking me shaving; the girls lying either side of me when I was doing sit-ups and raising their arms and legs shouting, "Look at us Mummy, we're exercising"; Alex and I sitting on the same armchair watching The Simpsons - him making unflattering comparisons between Homer and me.

I - and the family - really, genuinely changed. When Eve drew all over my sketchbook I didn't lose my temper. When Harry took to creeping out of his bunk bed in the middle of the night and sleeping under our bed, rather than shouting at the little lad, I lay down on the floor next to him and asked him why he did it. "Because I don't like rectangles, Daddy" was his reply.

It wasn't just the family routine that I was increasingly happy with - I was also starting to get on top of my personal game. For the first time since I was 19, I was at my ideal weight. It hadn't been easy, but I had stumbled on a workable weight loss regime and I loved how it made me feel. I'd kicked the booze; I was swimming seriously and I was running again.

It had taken nine months, but I had found - or created - a set of circumstances I had no desire to change. Then disaster struck. I was offered a job.

Much as I was loving time off work, I knew I would have to start earning again soon. The question was, could I go back to work and retain the changed parts of my life and the attitude that I had come to value deeply? With trepidation, I went back to the hamster wheel.

And all too soon I was bringing my work home. I started to shout at the kids again. One morning, during my second week back, I managed to make all four of them cry before Kate woke up - a bizarre achievement for someone who was supposed to have changed his outlook on life in general and family in particular.

A whole generation of women has long since realised that the "you can have it all" dream was just that - a dream. This is a lesson that seems to have been lost on men, though there are signs that a more honest debate is beginning. The business magazine Fast Company led with a front-cover splash "Balance is bunk!" in its October 2004 issue, with an article inside calling the idea of work/life balance fatally flawed. "It is an unattainable pipe dream, a vain artifice that offers mostly rhetorical solutions to problems of logistics and economics. The quest for balance between work and life, as we've come to think of it, isn't just a losing proposition; it's a hurtful, destructive one."

The debate has also got to be honest on an individual level. I have a confession - looking after four young children isn't always as rewarding as performing well in a business meeting. It is sometimes fantastic to be able to leave the domestic chores behind and go on a business trip. I do get a large part of my identity from my role at work. I'm competitive and find winning a thrill - not at all costs, but I am prepared to make personal sacrifices to achieve commercial victory.

So am I recommending all men just give up trying to lead more balanced lives? No, I'm not recommending anything. I haven't got any answers. But I do look at things differently now. I have stopped looking for perfection. Life is hard. Most of us will have to struggle, whatever choices we make. Admitting this to myself was liberating. I started to put my focus on trying to enjoy the struggle rather than attempting to create a mythical stress-free nirvana. I started to praise myself for the small victories rather than beat myself up for the bigger failure of not having a perfect life.

Now, every time one of the kids does or says something gorgeous, instead of descending into a pit of despair because I'm missing all the other gorgeous moments, I count myself lucky that I was present for that one. I'm grateful for every time I manage to drive the kids to school rather than resentful for those times that I can't.

I, of course, continue to be a deeply flawed executive, father and husband, but my year off started me on a personal journey. I'm still sober; I'm trim - no six pack yet, but definitely still trim; and the bond with my children has been permanently improved. I may be struggling being back at work, but I'm happy. I'm happy with the year off and I'm happy with the year ahead. Struggle and all.

Fat, Forty and Fired by Nigel Marsh is published on 8 June by Piatkus Books. To order a copy for £7.99 with free UK p&p go to theguardian.com/bookshop or call 0870 836 0875. © Nigel Marsh 2006