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.