Do you need to prove fault to start a divorce in Illinois? Divorce law in Illinois has changed dramatically in recent decades. For most of the state’s history, spouses seeking a divorce had to allege fault—adultery, cruelty, abandonment, or similar misconduct. That all changed with the 2016 amendments to the Illinois Marriage and Dissolution of Marriage Act (750 ILCS 5/), which made “irreconcilable differences” the sole ground for divorce in Illinois. This reform reshaped the legal process, emotional dynamics, and privacy expectations for families navigating dissolution.
The Move from Fault to No-Fault Divorce
From as early as 1874, Illinois law listed specific fault-based justifications for divorce. Each required proof, testimony, and often public disclosure of intimate details in open court. The process was emotionally taxing and socially charged. Lawmakers, concerned about divorce’s moral implications, even imposed a mandatory one-year waiting period in 1905 before remarriage could occur—two years if adultery was involved.