In the classic marriage vow (誓约), couples promise to stay together in sickness and in health . But a new study finds that the risk of divorce among older couples rises when the wife — not the husband — becomes seriously ill . " Married women diagnosed with a serious health condition may find themselves struggling with the impact of their disease while also experiencing the stress of divorce ," said researcher Amelia Karraker . Karraker and co - author Kenzie Latham analyzed 20 years of data on 2,717 marriages from a study conducted by Indiana University since 1992. At the time of the first interview , at least one of the partners was over the age of 50. The researchers examined how the onset (发生) of four serious physical illnesses affected marriages . They found that , overall , 31% of marriages ended in divorce over the period studied . The incidence of new chronic (慢性的) illness onset increased over time as well , with more husbands than wives developing serious health problems . " We found that women are doubly vulnerable to marital break - up in the face of illness ," Karraker said . " They're more likely to be widowed , and if they're the ones who become ill , they're more likely to get divorced ." While the study didn't assess why divorce is more likely when wives but not husbands become seriously ill , Karraker offers a few possible reasons . " Gender norms and social expectations about caregiving may make it more difficult for men to provide care to sick spouses ," Karraker said . " And because of the imbalance in marriage markets , especially in older ages , divorced men have more choices among prospective partners than divorced women ." Given the increasing concern about health care costs for the aging population , Karraker believes policymakers should be aware of the relationship between disease and risk of divorce . " Offering support services to spouses caring for their other halves may reduce marital stress and prevent divorce at older ages ," she said . " But it's also important to recognize that the pressure to divorce may be health - related and that sick ex - wives may need additional care and services to prevent worsening health and increased health costs ."