How much does your weight actually affect your marriage? Well, results of a new study may surprise you.

Researchers from the University of Tennessee followed 169 newlywed couples under the age of 35 over a four-year period in order to examine “the implications” of someone’s own body mass index (BMI) and their partners’ BMI for the “trajectory of marital satisfaction.”

After gathering all the data, researchers found men who had a higher BMI than their wives were happier at the end of the four years. In essence, these husbands were more satisfied in their relationships when their wives were skinnier – and the thinner wives were also significantly happier than other women in the study who had the same BMI as their husbands or higher.

“Husbands were more satisfied initially, and wives were more satisfied over time to the extent that wives had lower BMIs than their husbands, controlling for depression, income, education, and whether the relationship ended in divorce,” the researchers wrote in their report, which is featured in the July issue of Social Psychological and Personality Science.

“The great take-home message from our study is that women of any size can be happy in their relationships with the right partner,” Andrea Melzer, a doctoral candidate who worked on the study, told ABC News. “It's relative weight that matters, not absolute weight. It's not that they have to be small.”

Body mass index is the measure of body fat based on height and weight. Click here to calculate your BMI from the National Institutes of Health.