You’ve probably heard of a prenuptial agreement—a contract a couple makes prior to wedding that defines the way in which property will be distributed in the event of a divorce. Many people have preconceived notions about such an agreement, believing it indicates a couple’s lack of trust in each other or certainty that the marriage will last.

A postnuptial agreement is a less widely known type of marriage contract. Unlike a prenup, it is an agreement that is made between two spouses after they’re already married. The interesting thing with postnups is they have been shown to actually help a relationship that’s on the rocks.

Okay, we know what you’re thinking. You get married. A year or two go by, and suddenly you want to negotiate the terms of your hypothetical divorce? How could this possibly be a good thing for your relationship? Here’s how:

One of the most serious and common sources of tension in a marriage is money. Many couples have differing approaches to money, and may often fight over their finances. If you are a person who values financial stability, and your spouse has just cashed in their 401(k) to finance a trip to Bora Bora, chances are money is adding high stress and anxiety to your marriage.

This is where a postnup can be helpful—even cathartic. A couple is given the opportunity to vent their frustrations or concerns surrounding money, and then work together to come up with tangible solutions. Postnuptial agreements can effectively eliminate the leading source of negativity in a relationship. Some couples have even credited their postnup to saving their marriage.

You wouldn’t enter into a business partnership without a contract. Why should a marriage—arguably the most important partnership of your life—be any different?