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Updating your prenup: When does a postnup make sense?

On Behalf of | Sep 18, 2026 | Property Division

If you and your spouse put a prenuptial agreement in place before you got married, you took an important step that too many people still don’t. If you’ve been married for a number of years or maybe even decades, you may not have given that prenup any thought in some time. You may even believe that it “expired.”

Unless you included a sunset provision specifying that it would no longer be valid after a specified number of years or other milestone, however, that prenup could be deemed valid should you divorce and one or both of you want to use it.

What kind of circumstances warrant a postnup?

Likely, however, some things have changed since you put your prenup in place. 

  • Maybe you or your spouse is earning considerably more than the other. 
  • Perhaps one of you has chosen to leave the full-time workforce to raise your children or be a caregiver to another family member.
  • One or both of you may have started a business or created valuable intellectual property (IP).
  • One or both of you may have received a large inheritance that you want to protect.

On the negative side, maybe one of you has accumulated considerable debt or made some bad investments. Maybe one of you has developed a chronic illness that has made it difficult to work and therefore to support yourself if the marriage ended.

You can’t technically modify your prenup once you’re married. However, you can create a postnuptial agreement, which essentially does just that. Even if you foresee your marriage continuing, it’s always wise to have an agreement in place that reflects your financial circumstances and protects your interests in the event of a divorce.

What a postnup can and can’t do

A postnup can address the same matters as a prenup – largely property division and spousal support. However, it is not meant to address child custody or support. Those matters are meant to be determined by a judge if parents divorce based on a child’s best interests.

Even if you remain together “til death do you part,” a well-crafted postnup can still help you and your spouse develop a clear understanding of what assets belong to each of you individually and which you fully share. It can also help a lesser- or non-earning spouse feel more valued for their contributions to the family. 

As with a prenup, you and your spouse should have your own legal representative when putting a postnup in place. This helps ensure that the agreement is legally valid and protects both of you.