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 Massachusetts, spouses seeking a divorce can file on either fault or no-fault grounds. No-fault divorce is based on an 'irretrievable breakdown of the marriage' and can be filed as an uncontested action if both parties agree, or as a contested action if there is no agreement. For fault-based divorces, Massachusetts recognizes several grounds including adultery, desertion, gross and confirmed habits of intoxication, cruel and abusive treatment, non-support, impotency, and a prison sentence of five years or more. While Massachusetts allows for fault-based divorces, the court may consider fault when dividing marital property, but it is just one of many factors that the court will take into account. The division of property is ultimately based on what is considered fair and equitable, which may not necessarily mean equal. Additionally, allegations of fault may impact determinations of spousal support and child custody. The specific statutes governing these aspects of divorce in Massachusetts can be found in the Massachusetts General Laws under the Domestic Relations Section.