Researchers at Iowa State University looked at 2,701 couples over the age of 50 from the Health and Retirement Study, conducted between 1992 and 2010. They wanted to see if a diagnosis of cancer, heart problems, lung disease and/or stroke could potentially affect marital outcomes. And it did, but only for women: A wife's major illness was associated with a 6 percent higher probability of subsequent divorce, while a husband's illness had no effect on divorce rates whatsoever.