Traditional marriage vows have been repeated so many times that, to many of us, they are a cliche: for better or worse, for richer or poorer, in sickness and in health. Truth be told, vows are only words until they are put into practice. And when things go from “in health” to “in sickness,” it can put a real strain on a marriage.

This is evidenced by a new study put out by University of Michigan researchers. The study looked at more than 2,700 couples where one or both partners had a significant illness, and found that almost a third of those couples’ marriages ended in divorce. More significantly, and perhaps more surprisingly, when it came to older couples, a divorce was more likely when the wife was ill, rather than when the husband was.

There are several explanations for why this might be the case. One theory is that men, by and large, are not very good at being caregivers. Women who have the option might choose to seek support from friends and family instead. This idea is backed up by the fact that wives generally are the ones to file for divorce, rather than husbands.

An immediate divorce might not be the best course of action for all couples; it may be that a legal separation is the logical way to proceed. Every couple is different, however, so it may be useful to consult with an experienced divorce attorney to determine what would be the most beneficial step to take.

Source: Time, “Divorce More Likely When Wife Falls Ill,” Alexandra Sifferlin, May 1, 2014