Catherine Zeta Jones is often in the news along with her husband actor Michael Douglas. Catherine looking every inch the beautiful, blooming mother, is many years Michael's junior. How long will it last?

Why do people pair off across such great age gaps? Usually, let's face it, the man is older - it seems to be the convention. What is the essential ingredient that makes up for the age gap? Wealth, fame, power or unadulterated sex appeal can, of course, be very seductive outweighing grey hairs or an impending hip replacement. But isn't this being horribly cynical? True happiness has little to do with such stuff ...or does it?

 "I'm single now, but my last longstanding girlfriend was four years older than me. It really wasn't important at the beginning, but eventually it turned out that her agenda was different - she wanted to think about having children and for her this was important. After all, a woman has only got so many years in which she can do this thing. I guess, I'm just not ready for that kind of responsibility. I felt really guiIty - as if I had been wasting her time. The tension around this was what led us to split in the end - sadly."

" I'm from a middle-Eastern background and in our culture it's not so unusual for men to marry much younger women, at least it was like this in the past. But now, with women being less dependent and having their own careers, they want someone they can relate to on a more equal basis. Women don't need a man to look after them like in the old days - and who wants to be a widow in her fifties? I want a partner I can grow old with - I don't want to end up being a nursemaid to some old man whose twinkle has long gone."

"In my work I notice the age factor and its changing significance as relationships develop ... a lot of men in middle age have a fantasy about regaining lost youth by replacing the wife with a younger version. The ‘trophy' woman, maybe ten or more years younger, is a symbol of an identity crisis any of us can face as we have to let go of the dreams of our youth. We all think we look younger than we do ... our friends tell us this at every birthday … so providing the man has some social standing, and maybe professional success and is in reasonable physical nick then he can get away with going for a much younger partner. What he might forget is that someone ten years younger belongs to a different generation and may have fewer interests to share. It's not a strong basis for a lasting partnership."

"This is all so much rubbish! If the chemistry's there then it doesn't matter about age gaps - either way round! It makes me want to puke when people try and analyse what love is. Either it's there or it's not. I do want to find a partner before I'm forty, but only because my bio-clock is nudging me. Most of my friends are younger than me and I share more with that generation than with people who are older. Spare me the pipe and slippers syndrome! I know I look good and I see no reason why I should settle for some old fogey!"

"I've been there and done it. Had a relationship with a significantly younger woman after my divorce five years ago. I think I'd something to prove … she's gone to work abroad now and her career's developing. I just don't buy this younger model business. We simply wanted different things ... children were on her shopping list, but I don't want any more. For heaven's sake, mine are in their twenties now…… I can't do that again. Mind you, I wouldn't want to go out with anyone actually older than me! Except just as a friend…"