Years of being trapped in a bad marriage can break your heart, scientists have said.
A study found people who have experienced decades of conflict with their spouse are more likely to develop heart disease.
The finding was especially true for wives, possibly because women tend to internalise negative feelings more than men.
It says relationship counselling should be directed at older couples as well as newlyweds.
"Counselling is focused largely on younger couples, but these results show marital quality is just as important at older ages, even when the couple has been married 50 years," said sociologist Hui Lui, of Michigan State University.
Dr Lui's team analysed five years of data from 1,200 married men and women who were aged 57 to 85 at the start of the study.
All were participants in a US investigation that included questions on marital quality and looked at rates of heart attack and stroke.
The study found that bad marriages tainted by rows, criticism and demands were more harmful to the heart than good supportive ones were beneficial.
Stress from a bad marriage may become more harmful because of declining immune function and frailty, the researchers believe.
Women, but not men, also appeared to experience a decline in marital quality as a result of suffering heart disease.