It is a strange irony that the thing we want most in life is often that which eludes us. The writer and feminist Rebecca Solnit says, “Often it is the desire between us and the object of desire that fills the space in between with the blue of longing.”

The protagonist in my debut novel, The Imposter, wrestles with the sensation that Solnit describes – that blue of longing. She travels on the top deck of the bus in the city where she lives, glancing into the cosy living room windows she passes, filled with seemingly happy families, and longs to be a part of one of them.

There is much, in that respect, that I have in common with my invented character: that desire to belong. The first place we belong is within our own family and if we don’t feel we fit snugly within the rest of those jigsaw pieces carved just for us, it can leave a lasting impression. It can manifest as a desire and a longing to recreate that same unit when we grow and have families of our own. Or at least it did in me.

My own childhood was by no means as tough as some, yet I often felt like a cuckoo in the nest. My parents divorced when I was five and both of them went on to have new marriages and more children. I felt shunted between these two new families, never feeling I fully belonged in either. My father was a workaholic I rarely saw and my stepfather a drinker who at times made our lives hell. My step-parents were never going to feel the same about me as they did their own offspring, and so I felt keenly the disparity between the family life I idealised and the one I had been landed with. Instead, I looked outside my family, spending much of my time as a child at our nextdoor neighbours’ house, hoping to blend into their furniture and among their children so I wouldn’t have to return home.

I craved something perfect, something that would stick, and yet somehow always ended up creating the opposite – clearly my neighbours were never going to feel the same about me as they did their own children. And so, that blue of longing settled inside my bones.

I worked hard in my 20s and 30s as a journalist and editor on magazines and national newspapers. There is perhaps a sense of being on the inside that journalism offers, from national newsrooms where you were once – pre-internet – first to hear the news, to the hours spent sitting in other cosy living rooms, listening to secrets that had not been spilled before to another soul.

I moved from newspapers to books, and there was an intimacy to be found, too, in my job as ghostwriter. During the time I work with someone to write their memoir, I become an imposter myself, occupying their “I” rather than my own. I see the world through their eyes. I write with their voice. There is no sense of being on the outside, looking in. I am transparent, a ghost, there is perhaps only a wisp of my touch, but I am there, tucked between the words that appear on the page.

There are those among us who believe parenthood will secure us in something that will stick, although I can’t claim this was a knowable force within me. I was far too busy with my career to think about having a child, until I fell in love. In motherhood I found a whole different sense of belonging, though it would not be the same one I had pursued. I am not the first woman to have been let down by the whispered promises of a man. Suffice it to say, I brought my baby daughter home alone from the hospital and stared at her in her car seat, wondering how I would make it all work as a family of two.

There were, over the years that followed, both arrivals and departures by my daughter’s father, and I have a few photographs of the three of us, snapshots taken on holidays where we look like the perfect family, the picture of that which I had so desired – the same type of family that would make the woman in my novel green with envy. But I have had to remind myself how hard I had to work for those moments, how often they were little more than split seconds – and what reality lay behind those smiles. It’s hard seeing on social media those same families that you yourself envy when you are the sole carer and provider. How easy parenting looks viewed through that lonely lens: what a luxury to have someone else contributing to the mortgage; or sharing the nightfeeds; or giving you five minutes’ break so you can eat your dinner between breastfeeds. I remember well the evenings I would watch my meal for one burn in the oven while I was trapped under the weight of my baby, lost in a milky sleep. Strangely, it wasn’t the struggles of parenthood I wished I had someone to share with, but the joys – the first steps, the first day at school, the delight on your child’s face the first time she rides a bike without stabilisers.

The sting in the tail of single parenthood is that you, more often than not, spend time with the very families that have eluded you and your child; those safe little units you had so wanted to be your very own. You crave the mundanity of sitting in silence with someone in front of the television, both of you staring at your phones – even that seems more appealing than the ringing silence of the house once you’ve put your child to bed. You’re exhausted in those moments and yet suddenly they make a ghost of you. After you put your child to bed and realise you suddenly lack purpose in the dark.

I found it impossible not to feel like an imposter myself, for many, many years. I felt that in some way, I didn’t measure up to all these other families who were doing things “the right way”. Yet how strange that I should feel I was lacking when I had created two people out of one – I was both Mum and Dad.

But that is all I could see for a long time: the space where the other parent should have existed. The baby years went by, as did the toddler years and suddenly my child was six, seven, eight and I realised that I had spent too much time living in lack to notice just how precious our little unit of two had been. I wasn’t focused on just what we had achieved: the travelling we had done; the tour of Japan that we had undertaken; the building site we lived in while we renovated our little home; the seven books that I had written in the spaces between bathtime, sleep routines and school runs. There was nothing of the imposter about me or my child.

I realised I was living in regret at my own childhood, in this blue of longing for the perfect family I hadn’t had and had failed to create as a parent myself. But in living there, I risked my daughter feeling the same sense of loss creeping into her heart. I had to exorcise those ghosts of the past – and the only way to do that was to see things differently.

When I looked at my friends, the very same people I envied, I realised there weren’t really any perfect families. I saw those units struggling to shield their children from one parent’s addiction; or those who presented the perfect veneer while I heard stories of their cheating husbands; those sharing their lives unhappily without love because they feared what lay on the other side. And what was that? Something like my daughter and I had?

It has taken the writing of my novel for me to admit I am obsessed with the idea of belonging. Yet I have found belonging in ways I hadn’t considered: in the small, intimate moments I share with my daughter, those secret moments only a single parent and child know, when there are just the two of you against the world. I have found belonging between the words I write, whether they are mine or someone else’s. Belonging is perhaps not the state of arrival I believed it to be; it is the journey, it is making peace with that blue of longing, or more likely riding along on the wave of it towards a horizon that – if you open your eyes just a little wider – can be even more beautiful than the one you had once imagined.

I won’t tell you whether the protagonist in my novel finds her own sense of belonging, but what I will confide in you is that whatever the ending, it won’t resemble anything like a traditional idea of perfect. Because that is simply a mirage.

The Imposter, by Anna Wharton, is published by Mantle, priced at £16.99. Buy it for £14.78 at guardianbookshop.com