I'm a grown up, rational woman of 43 with a strong moral code, loads of fab friends, a great career and a terrible secret. Let me explain. I'm struggling to come to terms with the fact that my future won't include children of my own.

Days like today are especially difficult. I'm in the supermarket and witness one of those scenes that you want to look away from - a parent is going into total meltdown with a toddler. She's beyond angry; he's clearly terrified. All sorts of irrational thoughts flood my mind. I was supposed to be the mummy. Why has fate apparently dealt us the wrong life? Couldn't we just swap?

Don't panic, this isn't the confessions of a child snatcher, but it's just, well, so unfair. I can't do lots of things, such as play a musical instrument, or ski. But I'm good with kids. It's my thing. I grew up being told what a great mother I'd make. I was sure my "childbearing hips", which seemed so unfair when I was 14, would finally come in handy when I eventually gave birth. At 29, about to get married to a man who wanted children as much as I did, I gave up doing sit-ups and waited for the natural order of things to take over. And waited.

But every month we had our hopes dashed. We had "unexplained infertility", a common but deeply unsatisfying state of affairs. I wanted them to find something wrong with me - or him - so they could fix it. We tried intrauterine insemination (IUI) without success, and couldn't afford to pursue it further. We thought about IVF, but eventually the stress took its toll on our marriage, and we split up. I was 37.

I still wanted children, but not alone. Sperm donor? Adoption? I wasn't sure I was strong or secure enough to start another new battle that could take years to resolve or, yet again, result in disappointment. I decided to focus on being a brilliant auntie instead. My adored brother and his lovely wife now have four wonderful children. And I'm a "sort of" to my many wonderful friends' gorgeous children.

They're all a terrifically important part of my life, but I still haven't quite worked out what the point of my life is now. What my role is. I feel cheated. Something I grew up thinking would happen with a certain inevitability hasn't happened, and it has totally thrown me and some of my core beliefs. A friend of mine has had seven miscarriages. Crying together about her latest lost, I confessed I was jealous. That sounds awful, but she understood. She at least knows what it's like to be pregnant, what it's like to be a woman. I crave that. Even if it's just that.

She and I are voyeurs in a child-friendly world. Even a simple walk in the park can be hurtful. I giggle at the kids screeching in joy as they are pushed on the swings. I see the "No unaccompanied adults" sign. I'm a freak, not part of the gang.

Some people assume I chose not to have children because I'm a career girl, a party girl, have such a busy life. They don't see that some people are trying to fill the vacuum. I honestly don't know where I'll go from here. In writing this, I've unlocked some of the pain I thought I had dealt with. But I'm a deeply optimistic soul, with a lust for life. My future might include fostering. It'll definitely include being grateful for my wonderful friends and family. Last year on Mother's Day, my own mum bought me flowers to say thank you for being me. It made me cry with joy.

Getting Help

Often people who think they've accepted involuntary childlessness find that it hits them again and again, says Susan Seenan of Infertility Network UK - perhaps when friends are about to become grandparents, or when parents die or spouses die and they feel very alone.

It's thought around one in ten couples will suffer from involuntary childlessness, plunging many into depression. And childlessness will also cause one in three relationships to break down.

But help is available. More To Life offers a chance to share experiences, coping strategies and lists books that may help. Call 0800-0087464 or visit