The research consisted of over 160 just married couples who found that the happier they were in their relationship, the more pounds they gained.
During a four year time period, the couples were questioned regularly on their happiness within their marriage. They rated happiness on a scale and their height and weight was also taken.
The investigators found that for each unit increase in satisfaction, on average, males and females both gained one tenth of a BMI unit every six months - or one a pound a year for a female who is five feet, four inches tall and weighs 119 lbs.
The authors say the outcomes imply that those who were satisfied with their significant others might be less inclined to worry about their weight, because they had no desire to look elsewhere to find love.
Dr Andrea Meltzer, of the Southern Methodist University, Dallas, said:
"On average, spouses who were more satisfied with their marriage were less likely to consider leaving their marriage, and they gained more weight. In contrast, couples who were less satisfied in their relationship tended to gain less weight over time."
The couples that stayed happily together were more likely to put on weight; on the other hand divorce was linked to weight loss.
"These findings suggest people perhaps are thinking about their weight in terms of appearance rather than health," Dr Meltzer said.
The findings, published in the journal Health Psychology, recommends young couples be educated about weight management and how it contributes as factor to their overall health.
Previous studies have indicated weight-maitenance is normally motivated by the want to attract a mate.
Dr Meltzer concluded, "By focusing more on weight in terms of health as opposed to appearance, satisfied couples may be able to avoid potentially unhealthy weight gain."
Just days ago, a separate study was released suggesting more couples are choosing cohabitation over marriage. Couples are now choosing to live together before marriage, and many become pregnant before taking their vows as well.
Written by Kelly Fitzgerald