What Do I Do if My Prenup Is No Longer Fair?

 Posted on December 04, 2025 in Prenuptial Agreements

Over time, life can change in ways no one expected. If your prenuptial agreement no longer feels fair, you have legal options. Illinois law allows you to review, amend, or challenge an agreement that no longer fits your circumstances. Speaking with an experienced Rolling Meadows, IL prenuptial agreement lawyer is the first step. At Law Offices of Donald J. Cosley, we can help you draft a fair, enforceable agreement.

Can a Prenup Be Changed After Marriage in Illinois?

As a couple, you might buy a new home together, welcome a child, or build a successful business. With each change, your original prenuptial agreement may make less and less sense. In such situations, it is common to update the agreement or even nullify it and create a new postnuptial agreement that better reflects your current life and goals.

Under 750 ILCS 10/6 of the Illinois Uniform Premarital Agreement Act, you and your spouse can modify or revoke your prenup after marriage. The change must be in writing and signed by both of you. Oral changes are not legally valid.

Before making any changes, you need to have your own attorney review the agreement. Having separate legal guidance protects both of you and helps keep the process fair. It also reduces the risk of future disagreements if the agreement is ever questioned in court.

Life Changes That Can Make a Prenup Unfair Over Time

Common life events that can affect fairness include:

• One spouse leaving a job to raise children or care for a relative

• A business started before marriage growing in value

• A spouse becoming seriously ill or disabled

• The couple’s financial balance changing because of debt or inheritance

When these things happen, an agreement that limits spousal support or divides assets unequally can become unfair.

What Makes a Prenup Legally Invalid or Unenforceable?

Illinois courts can refuse to enforce a prenup if it is unconscionable, meaning it is so one-sided that enforcing it would be unjust. Under 750 ILCS 10/7, an agreement may be considered invalid if one spouse was pressured to sign, did not get a chance to speak with a lawyer, or was deceived in some way about assets or debts. Judges look at whether the agreement was fair when it was made and whether enforcing it now would be unjust. Even if it once seemed balanced, major changes in your life or finances may be relevant when a court decides whether the agreement should be enforced.

How Can You Challenge a Prenup During Divorce in Illinois?

If you believe your prenup is unfair, you can challenge it in court during your divorce. Your lawyer can help you gather evidence, such as financial statements or emails, that show the agreement no longer reflects your situation.

You may also file a motion asking the judge to invalidate all or part of the agreement. Courts will evaluate the fairness of the terms, the process used to create the document, and whether both parties understood what they were signing. In some cases, a judge may keep most of the agreement but remove certain provisions.

Under 750 ILCS 10/4, Illinois law sets specific limits on what prenups can include. An attorney can help determine whether any provisions in your agreement violate those rules.

Schedule a Free Consultation With Our Arlington Heights, IL Prenuptial Agreement Attorney

Attorney Donald J. Cosley personally manages every aspect of his clients’ cases. When you have questions, you speak directly with him instead of going through a paralegal or assistant.

We can review your existing agreement and explain your options for modification or challenge. Attorney Cosley provides straightforward advice and committed representation to help you pursue a fair outcome.

Call Law Offices of Donald J. Cosley at 847-253-3100 today to schedule a free consultation with our Rolling Meadows, IL prenuptial agreement lawyer.