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 Maine (ME), spouses seeking a divorce can file on either fault or no-fault grounds. No-fault divorce is based on the assertion of irreconcilable differences between the spouses, indicating that the marriage has broken down beyond repair. On the other hand, fault-based divorces can be sought for several reasons, including adultery, extreme cruelty, desertion for a continuous period of at least one year, habitual drunkenness, gross and confirmed habits of intoxication from the use of drugs, cruel and abusive treatment, or the conviction of a crime punishable by imprisonment for more than one year. While Maine allows for both fault and no-fault divorces, the presence of fault can influence the court's decisions regarding the division of marital property, spousal support, and child custody. However, the court strives to divide marital property equitably, regardless of fault, unless the fault has economic implications or other substantial impacts on the marriage.