Feeling happy is good for everyone’s health, but sharing everyday happiness with a life partner brings even greater health benefits, according to new research from the University of California, Davis.

What is the secret to happiness? A new study published in Nature Human Behaviour shows that happiness can come from either within or from external influences, from both, or neither — and which is true differs across people.

New research in psychology has found that that older couples have lower levels of the stress hormone when their partners feel positive emotions. This effect was even stronger for people who reported higher satisfaction in their relationships.