No need for any more expensive gifts, romantic breaks or big bouquets of flowers.
It seems the secret to a happy marriage is completely free - a good night's sleep.
Psychologists have found that having seven or eight hours' sleep a night means partners are less likely to focus on the negative aspects of their relationship and more inclined to think about the bigger picture.
Researchers at Florida State University say sleep also helps to restore function in the prefrontal cortex, the part of the brain that manages self control, which is thought to improve our perception of relationships.
Although divorce rates in the UK are at their lowest levels of 40 years, the numbers separating every year are still significant.
About 260,000 couples in the UK get married each year but at the same time nearly 120,000 part.
Experts regard honesty, warmth and respect as the bedrock of any relationship.
But the latest study, in the Journal of Family Psychology, shows a good snooze is equally important.
Scientists asked 68 newlywed couples to record their sleep patterns for a week.
They also kept a diary on how they felt about their marriage and how rows affected their view of the relationship.
Finally, researchers used something called the Kansas Marital Satisfaction Scale to assess volunteers' levels of satisfaction with their sex lives, levels of affection, time spent together, partners' mood and how they resolved rows.
Husbands benefited most from a proper night's sleep, the study found.
Even on days where they fell out with their wives, they felt upbeat about their marital status - providing they had a good rest the night before.
The researchers said: 'Sleep is an important factor that affects marital satisfaction.
'Up to a third of married or cohabiting adults report that sleeps problems burden their relationship.'