“Happy wife, happy life” - or so the saying goes.
New research suggests, however, “happy wife, healthy life” may be a better fit.
Read more: Being kind could help you live longer
Scientists from Michigan State University found having an optimistic other half could help ward off cognitive decline.
Being in a relationship with an upbeat person is thought to motivate us to work out, eat well and quit smoking.
With research increasingly showing what is good for the heart is good for the brain, these lifestyle habits could help you stay sharp.
“We spend a lot of time with our partners,” said study author Dr William Chopik.
“They might encourage us to exercise, eat healthier or remind us to take our medicine.
“When your partner is optimistic and healthy, it can translate to similar outcomes in your own life.
“You actually do experience a rosier future by living longer and staving off cognitive illnesses.”
The scientists looked at nearly 4,500 heterosexual couples who took part in the Health and Retirement Study.
Optimism was measured at the start, with participants being asked the extent to which they agreed with statements like, “In uncertain times, I usually expect the best”.
Memory, word recall and attention tests were used to assess cognitive ability every 24 months for up to eight years.
Results, published in the Journal of Personality, suggest being with an optimistic partner helps a person maintain their memory and “mental status”.
“There's a sense where optimists lead by example and their partners follow their lead,” said Dr Chopik.
“While there's some research on people being jealous of their partner's good qualities or on having bad reactions to someone trying to control you, it is balanced with other research that shows being optimistic is associated with perceiving your relationship in a positive light.”
Optimism cannot be prescribed in the way medication is, however, the scientists claim it can be a learned behaviour.
“There are studies that show people have the power to change their personalities, as long as they engage in things that make them change,” said Dr Chopik.
“Part of it is wanting to change.
“There are also intervention programs that suggest you can build up optimism.”