Most people are familiar with the concept of a prenuptial agreement—the legal contract that a couple enters into before their marriage to protect their wealth in case of divorce. However, far fewer couples are aware of post-nuptial agreements. Unlike prenups, post-nups are legal contracts entered into after the marriage is already underway. Surprising to most, this document is a legal contract for unions that can have an enormously positive effect on a marriage, or on a divorce if a marriage can’t be saved. Below are just a few of the great benefits of post-nups.

Benefit #1: Sends a wake-up call. For spouses who are in denial about their own bad behavior, post-nups offer a much-needed wake-up call to those underlying issues and how they are harming the marriage.

Benefit #2: Catalyzes difficult but essential discussions. The post-nup offers a chance to discuss issues in a marriage that couples fail to otherwise talk about. It becomes a lot tougher to ignore when it's literally spelled out.

Benefit #3: Imposes accountability on both spouses. If your spouse knew he would lose money, custody or something else if he failed to live up to a post-nup’s provisions, wouldn’t he be more likely to do what the marriage needed to survive? Defining the consequences can have a resonating impact.

Benefit #4: Decreases game-playing. Instead of taking advantage of known spousal vulnerabilities through manipulation and combative behavior, the post-nup encourages honest, open discussion.

Benefit #5: Moves couples beyond a single moment in time. Is your marriage in troubled because one or both of you are fixated on a single instance of bad behavior? If so, a post-nup would help both of you broaden and deepen your discussion, focusing on the larger issues that are more important to sustaining the marriage.

Benefit #6: Offers incentives for behavioral change. The legal provisions in a post-nup might help your spouse become more aware of her problematic actions and work harder at changing them.

Benefit #7: Sets equitable terms for a settlement if a divorce can’t be avoided. Make better decisions about custody, finances and the like when you still have a chance of saving the marriage (versus when you’re in the midst of a divorce). You are both more likely to consider the fairness of settlement terms when you’re not seeking vengeance or under the tremendous financial and emotional stress of the divorce process.

Tom Gardiner is a prominent Chicago attorney and the head of the well-known legal firm Gardiner Koch Weisberg & Wrona. He was selected Illinois Super Lawyer eight years running and has taught at various Chicago-area law schools. His articles have been published in the Chicago Tribune, Screen magazine and the ABA Journal. His new book, "The Post-Nup Solution: How to Save a Marriage in Crisis—or End It Fairly" can be found here.