Hey, say relationships are hard work, but what, exactly, is a couple supposed to toil at? Buying each other more stuff? Giving each other more back-rubs? Paying someone to assemble their IKEA furniture so as to avoid the inevitable mid-Ektorp bloodshed?

A new paper suggests that the answer might be much easier: Just be optimistic about the future of your relationship. In a study recently published in the Journal of Personality and Social Psychology, Edward Lemay, a professor of psychology at the University of Maryland, found people who predicted that they would be satisfied with their relationship in the future were more committed to their partners and treated them more kindly in the present-day.

To study this rosy-hued element of relationships, called “forecasted satisfaction,” Lemay performed a series of experiments. First, he had participants rank how highly they scored across a series of previously established metrics of relationship commitment: how satisfied they are currently; how much they’ve invested in the relationship already (such as buying a house together, for example); and how good they think the alternatives to their relationship are (essentially, whether they think they could do better). They also answered a questionnaire about their expectations for the future of the relationship, responding to questions like, “I expect that I will be happy with this relationship in the future.” It turned out their sunny predictions for the future correlated strongly with how committed they were, over and above those other factors.

“People are on their best behavior when they think this relationship will be a happy one in the future”

Then, he asked 200 couples to record their feelings about the relationship each day. Those who said they expected to be happy with their partners in the future were more committed on any given day. Finally, he had another group of couples come into the lab on two different days, about a year apart. Those that were more optimistic about the future during their first visit became more committed to each other over the course of the year and were more accommodating of each others’ needs. The couples’ friends also said the optimistic forecasters seemed more committed to each other. Lemay also filmed the couples arguing about something they disagreed on, and independent raters said the optimistic forecasters had nicer, less-destructive fights.

“People are on their best behavior when they think this relationship will be a happy one in the future,” Lemay told me.

Interestingly, predicting future satisfaction isn’t quite the same as being satisfied currently. You could, for example, be in a long-distance relationship at the moment, but expect that an upcoming move to the same city will boost your relationship happiness levels. According to Lemay’s research, it’s thinking about that happy ending that keeps people committed.

So what to do if you simply aren’t a very optimistic person, in love or other domains? For those Debbie Downers dating Nattering Nabobs, Lemay suggests a behavioral hack. Simply think of something you believe will improve the quality of your relationship, like going on a date or vacation together. Do that thing, and you might just start seeing a brighter future for your partnership. Believe you’ll live happily ever after, in other words, and at least romantically, you’ll start living happier today.