Prickly disagreements that can mark the early and middle years of a marriage mellow with age as conflicts give way to humour and acceptance, according to a study.
Researchers from the University of California (UC), Berkeley in the US analysed videotaped conversations between 87 middle-aged and older husbands and wives who had been married for 15 to 35 years.
They tracked their emotional interactions over the course of 13 years.
The team found that as couples aged, they showed more humour and tenderness towards another.
The findings, published in the journal Emotion, showed an increase in such positive behaviours as humour and affection and a decrease in negative behaviours such as defensiveness and criticism.
The results challenge long-held theories that emotions flatten or deteriorate in old age and point instead to an emotionally positive trajectory for long-term married couples.
"Our findings shed light on one of the great paradoxes of late life," said Robert Levenson, a UC Berkeley psychology professor.
"Despite experiencing the loss of friends and family, older people in stable marriages are relatively happy and experience low rates of depression and anxiety. Marriage has been good for their mental health," Levenson said.
Consistent with previous findings, the study found that wives were more emotionally expressive than their husbands, and as they grew older they tended toward more domineering behaviour and less affection.
However, generally, across all the study's age and gender cohorts, negative behaviours decreased with age, researchers said.
"Given the links between positive emotion and health, these findings underscore the importance of intimate relationships as people age and the potential health benefits associated with marriage," said Alice Verstaen, who conducted the study as a PhD student at UC Berkeley and is now a postdoctoral fellow at the VA Puget Sound Health Care System in the US.
Researchers viewed 15-minute interactions between spouses in a laboratory setting as they discussed shared experiences and areas of conflict.
They tracked the emotional changes every few years.
The spouses' listening and speaking behaviours were coded and rated according to their facial expressions, body language, verbal content and tone of voice.
(With inputs from agencies.)