Does marriage make husbands or wives more grumpy? Yes, science says.

A new study may put an end to an age-old argument between husbands and wives: Who really changed from the sweet lover they first met?

The answer — according to research published in the journal Developmental Psychology — is both of them.

Sorry.

Researchers from the University of Georgia followed 169 heterosexual newlyweds for 18 months after their marriage to determine how their personalities changed, if at all. The data was all self-reported and then analyzed for the study. The lead researchers were all men.

The results might not be helpful for couples considering whether to tie the knot or hold off.

First, let's start with some of the better news, just in case you have an upcoming wedding.

Husbands become more conscientious, meaning they have a stronger desire to do what is morally right and will also devote more time to improving their quality of work, according to the study. Wives become less neurotic and prone to anxiety, the study reports.

Here's the bad news.

The study also found that husbands become less extroverted, as they likely spend more time home, and wives grew less open. And both partners grow less agreeable — or more unpleasant — within just the first 18 months of marriage, the study said.

David Woodsfellow, from the Woodsfellow Institute for Couple's Therapy, said that last piece of information probably isn't all that shocking for anyone who has exchanged vows before.

"It has a ring of truth," he wrote for Psychology Today. "Many people have experienced this. The good behavior of courtship tends to fade, old bad habits tend to return."

And don't think you might be a different type of person that can buck the changes. Researchers wrote that their findings were consistent regardless of: "spouses' age, demographics, relationship length prior to marriage, cohabitation prior to marriage, initial marital satisfaction, or parenthood status."

However, another study offers some good news! Research published in the journal Social Networks and the Life Course found that marriage can actually increase the happiness of partners — but it just takes 20 years of being together to reach that.

But before that, the researchers wrote, "happiness declined gradually during the first 20 years of marriage."

This story was originally published May 29, 2018 at 3:20 PM with the headline "Does marriage make husbands or wives more grumpy? Yes, science says.."