Kate, a married friend, said to me in that kindly patronising tone reserved for mad old women and naughty children: “Don't you think it's time you stopped running around like a middle-aged teenager and tied the knot before it's too late?”

“Too late for what?” I thought - a lifetime membership of Ikea and a man who is going to turn from Mr Perfect into Mr Sulk/Unfaithful/Slob within two years.

The truth is, while wedded bliss is great for some women, there are those of us who are not cut out to find a man, marry and reproduce. I am 43, unmarried, without a child and I am not crying myself to sleep.

Why should I? This is not the 19th century: I am not going to freeze to death in a workhouse. Nor is it the 20th century: I am not going to write an angsty desperate-to-be-married Bridget Jones-style diary or worry about the biological time bomb.

Welcome to the world of the Post- Modern Spinster. Sane and still in demand, the PMS has chosen her go-it-alone existence. She is part of a sisterhood that has forgone the traditional markers of conventional happiness - marriage, children - in favour of life on her terms.

It is not strictly a question of not finding Mr Right. I have been proposed to three times. I have been in a couple of long-term relationships. Each time the M-word has cropped up, I get the heebie-jeebies. I just don't have the marrying gene. It is not that I have anything against finding the man, it is the notion of the domesticity of settling down that makes me uncomfortable. The idea of jostling together, the never-ending compromises, the hours spent considering the needs of the family - ferrying kids to and from parties or having to wake at 5am because your husband has an important meeting in Paris - doesn't sound like fun.

And a lot of women, like me, are waking up to the idea that there is an alternative to the constraints of marriage and the drudgery of bringing up children. Over the past ten years the numbers of women who have decided to opt out of the family game have risen. According to statistics, 50 per cent of educated, professional women are unmarried and childless and, of those, two thirds have elected to be so.

This new breed of woman leads an interesting and fulfilling life. “I have so much free time to pursue my goals,” says my friend Emily, a chef who has spent the past year doing an MA in art. “My married friends spend most of their time worrying about their relationships or their children.”

Of course, happiness depends on what you consider to be personal contentment.

I have a fulfilling, uncompromised career, while most of my married friends have had to put their career on the back burner. I have a large circle of friends. I can go to the cinema whenever I please or just lounge in bed drinking cappuccinos and reading trashy celebrity magazines.

The PMS is a free spirit but, and I am the first to admit it, there is a price to pay for a refusal to compromise on my lifestyle and sleep quotient - not having the knowledge that there will always be someone waiting at home for you with a cup of cocoa and a cuddle can be daunting. And, yes, sexy and single can soon morph into wrinkly old lady surrounded by cats, but marriage doesn't guarantee a man for life either.

So a word to my judgmental friend. The next time you want to call someone a middle-aged teenager, ask yourself who's having the most fun.

Times recommends

• McDonald’s: the world’s local restaurant
• Help me to be a mum: a foyer to fulfilment
• A life online: God likes a laugh