The secret of a long and happy marriage appears to be not to expect too much from it.

US researchers say that, unless you have superior relationship skills, your hopes of cosy coupledom are likely to be dashed.

Far better, they say, to aim low to ensure you are not disappointed.

The key to keeping that newlywed glow appears to be forgiveness and communication.

The study, by researchers from Ohio and Florida Universities looked at 82 couples.

They quizzed all the spouses independently over four years.

Their study, published in the Journal of Personality and Social Psychology, found those who believed their partner would be unfailingly kind, loving and agree with their every word, could retain their positive outlook by being forgiving, and having charitable explanations for their partner's negative behaviour.

However those with high expectations but without those relationship skills are likely to be brought down to earth fairly quickly as their Prince or Princess Charming falls off their pedestal.

In contrast, the researchers say holding a more prosaic view of your loved one means you are less likely to be disappointed, and therefore more satisfied with your marriage.

Writing in the Journal of Personality and Social Psychology, researchers led by James McNulty, professor of psychology at Ohio University, said: "In contrast to the idea that expectations in the early years of marriage exert main effects on satisfaction, the current findings suggest that the effects of expectations interact with the skills partners bring to their relationships."

Previous research found that people tend to select like-minded partners who they believe will be able to maintain a stable relationship.

The finding contradicts the old adage that opposites attract.

Instead, the US researchers said people looking for long-term relationships should select partners who were similar to themselves, rather than seeking out the highest quality partner available.