Most states allow spouses seeking a divorce to allege fault in the breakup of the marriage as a basis for the divorce. Alleging the other spouse’s fault—rather than seeking the divorce on no-fault grounds (irreconcilable differences or incompatibility, making the marriage unsustainable)—is generally a basis for requesting the court make an uneven distribution of the marital or community property in favor of the spouse alleging the other’s spouse’s fault.

In states that allow a spouse to seek a divorce on fault grounds, the grounds that may be alleged vary from state to state, but generally include adultery, cruelty, conviction of a felony, family or domestic violence, abandonment, mental illness, and substance abuse (drugs and alcohol). Spouses may also seek a divorce on no-fault grounds in these states.

In no-fault states, a spouse is not allowed to allege fault as grounds for the divorce, and the court is not allowed to consider fault in dividing the marital or community property—but allegations of fault may be considered for other purposes, such as spousal support and child custody. No-fault states include California, Colorado, Florida, Hawaii, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, Oregon, Washington, and Wisconsin. And in some states “incurable insanity” is a no-fault ground for divorce.

The grounds on which a spouse may seek a divorce (fault or no-fault) are usually located in a state’s statutes—often in the family code or domestic relations code.

In Wyoming, spouses seeking a divorce have the option to file on either fault or no-fault grounds. No-fault divorce is based on the irretrievable breakdown of the marriage, where neither spouse is held responsible for the failure of the marriage. On the other hand, Wyoming law does allow for fault-based divorces, where one spouse can allege specific grounds as the reason for the dissolution of the marriage. The fault grounds recognized in Wyoming include adultery, cruelty or inhuman treatment, willful desertion, willful neglect, habitual drunkenness, and conviction of a felony. When a divorce is filed on fault grounds, the court may consider the fault in the division of marital property, potentially leading to an uneven distribution in favor of the non-faulting spouse. Additionally, fault may be relevant in determining spousal support and child custody. It's important to note that the specifics of how fault impacts the division of property and other divorce-related issues can vary, and an attorney can provide guidance tailored to the individual circumstances of the case.