We live in a culture that celebrates and exalts couples, but pigeonholes singles as outliers, misfits, and oddballs, who can’t find someone to love them.

Admitting you don’t have a partner usually prompts a furrow of the brow and a ‘There, there, you’ll meet someone soon.’

My father, now sadly departed, first called me a ‘spinster’ when I was 33. He didn’t say it in a jokey way. He was being straight-down-the-line serious. We were visiting my aunt and uncle when the inevitable question was asked: ‘So, any danger of you getting married, Catherine?’

My reply, explaining that I’d just broken up with a boyfriend I’d been living with but who hadn’t been treating me well, was met with frowns.

‘Well, you’re not getting any younger,’ my uncle said, at which my father guffawed. No one congratulated me for having left an unhealthy relationship.

On the way home, I joked that my aunt and uncle treated me like ‘a spinster’. My dad’s response? ‘Well, you are a spinster,’ he told me firmly. To him, a woman who reached her early 30s without finding a husband was ‘on the shelf’, ‘past it’. We had a huge argument in the car.

Catherine Gray, 38, (pictured) shares her unexpected joy at being single in a new book, she recalls spending her 20s trying anything to avoid being single

Never mind that his marriage to my mother had collapsed and another long-term engagement had failed. For my dad, the bottom line was that there was nothing worse than being a spinster, a woman on her own.

I was utterly distraught. Once I’d cried myself out, I tried to figure out why this had wounded me so much.

I realised I felt as if I’d failed as a woman, as a person, because I hadn’t found my life partner yet. I felt unchosen, unwanted.

Yet if being single is so terrible, why are more than half of us rejecting coupledom?

The most recent data, collated by Mintel in its Single Lifestyles 2017 report, found that 51 per cent of Britons aged 25 to 44 are single (that includes divorcees).

A typical British millennial (born after 1980, I am on the cusp of this generation) is expected to live alone, without a partner, for an average of 15 years, with only one in two expected to marry.

Meanwhile, the number of single households in Britain has more than doubled in the past 40 years.

Even though the statistics show that singles have tipped over into becoming the majority of under-45s, it still feels rebellious, trend-bucking, to be single beyond your 20s. Why? Because we are still living in the shadow of the nuclear family and groaning under the weight of our parents’ expectations.

The irony is that their experience may be a key reason why we are turning our backs on marriage.

During the raising of the Baby Boomer generation (those born roughly between 1946 and 1964), there was an almighty marriage spike, which is probably why our parents are so perplexed that we’re not married like they were by our age.

Back in the Sixties, marriage rates were at 80 per cent. Our parents came of age in a climate of ‘marriage is best’.

To them, marriage was the norm. It was simply what they did, and what their peers did. Being single was an aberration. The fact that until the Seventies a woman could not have a bank loan or a mortgage without a man to co-sign it may also have been a significant factor, meaning marriage gave financial security.

My mother, like so many of her generation, was married in her early 20s. At the age of 23, she was considered old in her social circle — my dad was 22.

To my mum’s generation, single isn’t a choice. It’s an undesirable period when you’re between men. It made me feel a total failure

This veneration of coupledom was something they duly passed on to us, their children.

Our parents taught us to fear being single. We were brainwashed into thinking that a happy-ever-after always involves finding a partner; to fear being on our own.

I know this fear intimately. It’s why I was never single in my 20s and instead swung from boyfriend to boyfriend. I thought any relationship, no matter how toxic, was better than none.

When I wasn’t with someone I felt flat and dark, like a pitch-black room that waits for someone to come along, flick on the light and animate it once more.

It never occurred to me that I could just be on my own, certainly never that I could be on my own and happy. And this wasn’t just me — these feelings were common among my friends.

Catherine (pictured) revealed she spent much of her 20s roaming desperately to find her other half and feeling 'broken' whenever she was single

I spent much of my 20s feeling that I was ‘broken’ somehow if I didn’t have a boyfriend. I bought into the idea of the ‘other half’ hook, line and heart-sinker and felt horribly incomplete when I was solo. I roamed around desperately seeking my missing other half.

But as a result, rather than love blossoming over me like wisteria, it had me in a poison ivy-esque chokehold, threatening my wellbeing. I used to do anything to avoid being single, including putting up with substandard treatment and dating people I wasn’t that into.

Recently, I thought back to my relationships and it dawned on me that I defined myself by the men in my life for more than a decade. It is only now that I understand why I was the way I was.

I grew up in a culture that prized romantic love, marriage, a happy ending. The conditioning didn’t come just from family but from television and advertising too — think of all those sitcoms and adverts with their perky families, from the Oxo ads to The Cosby Show.

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By the time I was 16 I’d witnessed my mother go through two divorces (though her third marriage has lasted over two decades), while my father had been through one divorce and the breakdown of an engagement.

Again, my experience has not been unusual among my contemporaries. Divorce rates in the UK rose during the Eighties and Nineties, and Baby Boomers are now the age group most likely to divorce. No wonder their children, who have come out the other side of dysfunctional homes or watched their parents split up later in life, are reluctant to marry.

You’d think, given their difficulties, that my parents would have done all they could to turn me off the idea of marriage. Yet, if anything, their rocky relationship history made them all the keener that I should not be alone, a scenario they feared more than anything.

To my mum’s generation, single wasn’t a choice, it was an undesirable period when you were between men. When I was in my twenties, and a serial dater on a frantic quest to find ‘The One’, my mum had never been single for more than a year in her adult life. This may help to explain why I once had to ban her from continually asking me about any men I’d mentioned going on a date with. ‘Has so-and-so been in touch?’ became an almost daily refrain.

Catherine (pictured) believes many people have raised the bar far higher than their parents when looking for a partner in the hopes of having a successful marriage

My brother and I used to joke about finding the most stereotypically unsuitable man we could and bringing him home to introduce him to my mum as my boyfriend, so she could find ways to justify liking him.

I could have brought home a man with a spider tattoo crawling over his face and she would have said: ‘He’s just so alternative! Gutsy in his style choices.’ She would have found a way to approve.

She wanted me to be half of a couple, not in the scary single world.

The widespread resistance to being single, the stigma attached to it, meant people routinely settled for, and stayed in, relationships they didn’t truly want.

But when we came of age, having taken in all those subliminal messages about romantic love and finding Mr Right, we raised the bar far higher than our parents when looking for a mate.

Our parents had instilled in us the importance of marriage —but unlike them, we were determined to have happy, successful ones.

Modern Romance, by Aziz Ansari and Eric Klinenberg, is a brilliant investigation of the modern dating landscape. It suggests that whereas our parents were willing to settle for ‘you’ll do marriages’, we now want ‘soulmate marriages’.

Back in the Sixties, 76 per cent of American women (and 35 per cent of men) were willing to marry someone they did not love. But by the Eighties, only 9 per cent of American women and 14 per cent of American men were up for marrying someone they didn’t love. An incredible shift.

Catherine (pictured) says when she was younger, she put being in a relationship above her personal happiness

However, this ultimately makes it harder to find a person we want to marry. In a 2013 TED talk (an online lecture), the psychotherapist Esther Perel analysed how our expectations have risen to unprecedented levels.

Not only do we want a partner for life to give us children, social status and companionship. ‘But in addition I want you to be my best friend and my trusted confidant and my passionate lover to boot,’ said Perel. ‘So we come to one person and we are basically asking them to give us what once an entire village used to provide . . . give me comfort, novelty, familiarity. Give me surprise.’

And we want all this to happen at exactly the right age, not too young, not too old. But as my generation is beginning to realise, this is a tall order.

Our perception was that relationships are euphoria-givers but the hard evidence, the reality, doesn’t match up to that wildly romanticised expectation. Research suggests that marriage gives only a brief bump in contentment. The message is that if you weren’t happy before marriage, you won’t somehow magically be happy afterwards.

When I was younger, I put being in a couple above my own happiness — and the modern-day dating scene compounded the confusion.

In some ways, dating apps and online dating have been a positive development, broadening the pool of possible partners, which inevitably shrinks as you get older.

But I’ve discovered that, paradoxically, when we’re given too much choice we become paralysed, dissatisfied and less likely to choose at all.

My mother grew up in a village where there was a pool of perhaps ten to choose from. In London, or any major city, I believe it’s actually impossible to scroll to the end of the choices on the dating app Tinder.

Catherine (pictured) claims people are more likely to check if someone they find attractive is on a dating app than to pluck up the courage to speak to them in person

The result is that you always think there is someone better for you out there, and end up bewildered by the choice of thousands and thousands.

Without a doubt dating apps have made dating more shallow and transactional. Everyone, including me, judges on looks first and foremost when using apps, even though we all know attraction is the whole package – looks and personality.

The days of plucking up the courage to go and chat up a man or woman are fast disappearing. If a man sees a woman he finds attractive in a bar, chances are he won’t go and talk to her but will, instead, go on a dating app that brings up available people by location, to see if she is there.

For those who do tie the knot, marriage is taking place later and later. The Office for National Statistics released a report in 2018 that stated: ‘For marriages of opposite-sex couples, the average (mean) age for men marrying in 2015 was 37.5 years, while for women it was 35.1 years.’

Out of my friends, half are still single but the other half were part of a mid-30s church rush. Many wanted to have children and had the age of 35 ringed in their heads with a black marker of doom as their fertility deadline.

In 1970, average marriage ages were 27 for men and 25 for women. So, compared with 1970, men are getting married almost 11 years later, while women are getting married ten years later.

What’s more, 42 per cent of marriages end in divorce, which means that almost half of those who walk hopefully and beaming down the aisle wind up suddenly single later in life.

I am not saying marriage is claptrap or claiming that being single is ‘better’. But it’s definitely not less than. Today’s young singles are often treated as Peter Pans, overgrown adolescents, grown ups in training. But perhaps many have made the right choice.

Catherine (pictured) believes the past two and a half years of being single have been the best years of her life

Women can now have sex outside marriage without community banishment; we can have socially accepted children without a husband; we can ensure a roof over our heads without the signature of a man; we can have stellar careers and earn almost as much as equivalent men, and we can choose not to marry without becoming an outcast.

Marriage can be a lovely thing. I'm all for two people choosing to make a public and lasting commitment to each other. If I were ever to have children, I’d want it to be within the stability of a marriage.

But I’m no longer entirely sure that marriage is a wise goal for all. Some blossom within it, while others wilt.

I have now been single, aside from brief flings that never even got into boyfriend/girlfriend territory, for nearly three years. And they have been the best years of my life.

I’m no longer frightened of being on my own. I can date without losing my marbles, and I have learned to luxuriate in my singleness rather than look longingly at couples, thinking: ‘I want that. Why don’t I have that?’

Ten years ago, at 28, being date-free for even a few months would have been unthinkable. I had to find a husband. But at the age of 38, my mind feels so much calmer now I’m not frantically looking for ‘The One’.

I’m not pledging to be single for ever. But I am reserving the right to choose to be single and to be proud of it.

Adapted from The Unexpected Joy of being Single, by Catherine Gray, published by Aster at £9.99. © Catherine Gray 2019. To order a copy for £7.99 (offer valid to 23/1/19; P&P free on orders over £15), visit www.mailshop.co.uk/books or call 0844 571 0640.