Type “Can having a baby save my relationship?” into Google, and the search engine will return more than 81 million results. The idea that a bundle of joy will fix what ails your love life is one of the most persistent relationship myths ever.

And that’s exactly what it is: a myth. New research published in Demography last August shows that the opposite is true. Having a baby makes people more unhappy than some of the worst life events out there: divorce, unemployment, and even the death of a spouse.

Other research, published in The Journal of Family Communication in 2005, found that 40 to 67 percent of couples with a new baby saw the quality of their marriage decrease “precipitously” within the baby’s first year. “The transition to parenthood and its associated decline in marital quality is part of this cascade toward divorce,” wrote the authors.

Another study, published in Journal of Family Psychology in 2000, found that one-third of all divorces take place within the first five years of marriage, and half within the first seven. “For many couples, the cascade toward divorce begins with the first decline in the wife’s marital satisfaction after the arrival of the first baby,” wrote the authors.

The decline in the quality of relationships soon after childbirth has many components, all of them painful. First of all, conflict between partners shoots up, followed by a decrease in the quality of the relationship in general. The relationship dynamics change, including increasing asymmetry in household labor, less conversation and sex, and more fatigue, irritability, and depression.

In fact, it seems safe to say that having your first baby might just be the biggest challenge your relationship will ever face. If you’re already on the rocks, it almost guarantees you won’t last much longer.

On the other hand, what might last longer if you have kids is your life itself.

A 2012 study published in Journal of Epidemiology and Community Health found that men who wanted to have children but couldn’t had a death rate twice as high as men who had children. Women who were frustrated in their desire to have children had a death rate four times higher than that of mothers.

And another study, from 2006, found that in those with agricultural lifestyles, the more children one has, the longer one lives. The study, focused on the Amish, found that fathers and mothers both lived a bit longer for each additional child they had (almost three extra months per child for men and more than four extra months per child for women).

So parenthood, it turns out, is quite the mixed blessing. The stork and its bundle might well ruin a shaky marriage, but it will also keep you around longer to wonder at the paradox of it all.