Is there an ideal age gap for a long lasting relationship?

I’m not sure if it’s trendy to date someone with a large age gap but I certainly seem to be seeing a lot more of it.

Kris Jenner 61, has split from her boyfriend Corey Gamble 36. Jodhi Meares, 46, has separated too from second husband Nicholas Tsindos, 29. And my favourite, the ‘world’s oldest fiancee, Valdemira Rodrigues has become engaged at the age of 106 to her 66-year-old toyboy, after they fell in love at first sight at a Brazilian retirement home.

So what is the ideal age gap? And should you be dating older or younger? Surprisingly, science has a lot to say on this.

According to a study from Emory University in the US, couples with a one-year age difference between them have just a three per cent chance of divorcing.

Compare that to an 18 per cent chance of divorce for a five year age gap, 39 per cent for a 10 year age gap, and a whopping 95 per cent for a 20 year age gap. After analysing 3000 couples, the researchers ultimately found the larger the age gap between a couple, the more likely they are to get a divorce.

I don’t think anyone would be surprised by the results of this study, but I wanted to know why? Does a large age gap cause problems with money, career, social life, personal tastes, wanting kids, all of the above? How does the age gap impact people in the real world?

My Aunty Maria has just turned 50, her husband is 66. Now that the kids have left home, she wants to go out to the movies, dinner and dancing, while all her husband wants to do is watch "Antiques Roadshow" and be in bed by 8.30pm.

My friend Sarah started dating a 47-year-old guy when she was 22. "When I first started dating Peter, more than once when we went out for dinner, the waitress would ask are you having dinner with your Dad? At first this bothered me but then I figured they were the ones with the problem."

Sarah's family was fine with the age gap:

"My dad was quite close in age to Peter, he just said it was my own journey and something that I had to grow through myself."

But it was a different matter with her new boyfriend's family.

"Peter's daughter wasn’t happy about it, she was 26 and I was 23, she had a few words with her dad, in the end she accepted it but she was never really comfortable with my age."

Sarah agreed that it was the age gap that caused the end of their relationship, saying "Peter's business was stable and he wanted kids and a mortgage, I was still studying and my career was just starting, I did want kids - but not as soon as he did."

Evolutionary psychologists say that younger women and older men often get together because while fertility lasts only from puberty to menopause in women, it starts at puberty and can extend long into midlife for men.

In evolutionary speak, that means there’s a strategic advantage for women to date an older man —he’s had more time to accumulate resources and stability than his younger counterparts, which could make him a more stable partner and father.

Som sociologists say a factor contributing to women dating younger men is the "marriage squeeze" where single "older" women have a smaller pool of potential mates. Then there is the reasoning that many women today have greater financial independence than in the past and this gives them more choices and more power.

But be aware: if you are dating someone with a large age gap there is one caveat to the Emory University study. The study also found couples who do manage to make it past the two-year mark, no matter what the age gap, are approximately 43 percent less likely to split up.

Ahh, if only relationships could be reduced to numbers.