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 Pennsylvania (PA), spouses seeking a divorce have the option to file on either fault or no-fault grounds. Fault grounds in Pennsylvania include adultery, cruelty, bigamy, imprisonment for two or more years, and willful desertion for one year or more. No-fault grounds can be based on irretrievable breakdown of the marriage, where spouses have lived separate and apart for at least one year, or mutual consent, where both parties agree the marriage is irretrievably broken. In PA, fault may be considered by the court when dividing marital property and may also affect alimony and spousal support. However, it is important to note that no-fault divorces are more common due to their typically simpler and less adversarial process.