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 Ohio, spouses seeking a divorce can file on either fault or no-fault grounds. No-fault divorce can be sought on the basis of 'incompatibility' unless denied by either party, or 'living separate and apart without cohabitation for one year.' Ohio law also provides several fault grounds for divorce, including adultery, extreme cruelty, fraudulent contract, any gross neglect of duty, habitual drunkenness, imprisonment of the other spouse, and procurement of a divorce outside the state to legally marry another. When fault grounds are alleged, they can influence the court's decisions regarding the division of marital property, spousal support, and child custody. However, the court will consider many factors when dividing property, and fault is just one of them. It's important to note that while fault can play a role in the financial and custodial outcomes of a divorce, the presence of fault does not necessarily guarantee an uneven distribution of assets or more favorable custody arrangements.