If opposites attract, does a fitness fanatic belong with a coach potato or will they be happier with a gym bunny?

Balance is the key, and whilst differences between two people increase the initial attraction, long-term happiness is usually thanks to similar ways of thought.

Psychologist George Feldman agrees. He explains that people pair off with others like themselves.

"It stems from when our ancestors ran the risk that if someone was very different, they might not be the same species," he explains to Company magazine about what he calls 'assortative mating'.

Not to say that couples with different cultures, backgrounds or religions are doomed in relationships. But chances are that they will probably face more struggles in making their relationship work.

Dating your mirror image isn't a good idea either. Boredom is likely to set in when two people always agree on everything and think the same way about every issue.

The trick is to find someone who is compatible with your fundamental values but with enough different characteristics and interests to keep you interested.

? Adfero Ltd