An expert has called it: This is the magic ratio to a long and happy marriage.

Navigating all the rules to a lasting relationship is mind-mashing.

Don’t fight about money, we’re told. Always communicate feelings openly, we’re urged. And whatever you do, never go to bed angry.

And those are only three of the squillions of happy marriage mantras.

But an expert has put forward a far simpler way of ensuring that your relationship remains on track: the 5:1 ratio.

Famed marriage expert Dr John Gottman says the key factor that distinguishes the happy couples from the miserable is a healthy balance between their positive and negative interactions.

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But, as explained on the Gottman Institute blog, balance does not mean a 50-50 equilibrium.

Dr Gottman’s theory is that there needs to be five times as many positive interactions between partners as there are negative for the relationship to be stable.

Dr Gottman calls this the “magic ratio”.

Positive interactions include touching, smiling, paying compliments, laughing, showing empathy, being kind and showing interest.

Negative interactions include criticism, hostility and anger.

“If you do something negative to hurt your partner’s feelings, you have to make up for it with five positive things,” Dr Gottman says.

“Negative has a lot more ability to inflict pain and damage than positive things have to heal and bring you closer.”

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The ratio can even predict the longevity of a relationship.

Gottman says couples who end up divorced tend have a 0.8:1 ratio — meaning there was a touch more negativity.

As the blog post states, the bottom line is this: “Even though some level of negativity is necessary for a stable relationship, positivity is what nourishes your love.”

“All couples have different styles of approaching conflicts – some yell and slam doors, while others retreat into separate corners of their home and fume quietly. Neither style necessarily spells relationship doom.”

Of course, realistically, it’s very hard to start measuring and counting every interaction between you and your partner.

But if you can in some way use this as a framework for what steps to take after a couple’s tiff, then that can only be thing.

As Gottman says, it’s just crucial that any rocky situations that arise are mended and compensated with regular demonstrations of appreciation and respect.

Roger that.