Invisible and unsolicited by everyone but M&S and Saga, you could be forgiven for thinking the world wouldn't notice if you disappeared. There's nothing like reaching that landmark as a woman to make you feel like your seat at the table, never having been at the head, is now in a different room altogether. Reaching your 50s, having just got there myself, plays havoc with your imagination. You are certainly depressed, and it's a condition that turns molehills into mountains, so I would strenuously recommend professional help. The people around you occupied with raising kids will, in a matter of years, be sitting at home without them, most likely despondent because their children, so lovingly raised, now can barely make it home for lunch on Sundays, if for that matter they even choose to remain within visiting distance. In principle it should be possible for your and you husband to offer a loving home to a child in need if you're sure parenthood is the only route to contentment. How far they've succeeded I'm not sure, but radical reform was needed, particularly on the age and ethnicity front now that our life span is increasing and we want children to grow up colour blind, not colour defined. This government should be applauded for its attempts to tackle the outdated and unnecessarily stringent rules around adoption.

If you're convinced that it's the key to your happiness there are routes open to you, whether with the help of modern medical science, marrying into a readymade one or through fostering and adoption. There are many ways to make the most of your time on the planet, and propagation of the species is just one of them. It could be argued that parenthood is elevated far above its rightful status in our massively overpopulated world where, conversely, children without parents exist in equally daunting numbers. But like any other choice you make, it's not all bounty. Though it's much easier to find them in commercials, magazines and movies than in real life.

Mariella replies It's hard to move for portraits of perfect parenthood, I agree. In our family-orientated society, I am constantly reminded of what I am missing, and increasingly feel I have nothing to live for. I get home from work feeling exhausted and isolated. We have separate interests and his hobbies mean I don't see much of him at weekends. He thinks our life is good as it is and that we should focus on what we have. I was desperate to have a child, but had three miscarriages instead.

I have been with my partner for 11 years, but sadly marriage has not brought me the sense of closeness or security I hoped it would. I was very close to my parents (now dead), and now that the family home is gone, too, I've lost the only stability I had in my life. I had an expat childhood, living in Europe and the US.

Although I have lived in the UK for 20 years, it has never really been 'home'. The dilemma I am 51 and feel alone and unsettled.

I am so lonely song redd8t