The grounds for divorce fall into two buckets. Every state allows a no-fault divorce, where you simply tell the court the marriage is broken beyond repair. About 33 states also allow fault-based divorce, where you accuse your spouse of specific misconduct such as adultery, cruelty, desertion, habitual substance abuse, a felony conviction, or incurable mental illness. The rest, roughly 17 states and the District of Columbia, are pure no-fault jurisdictions where fault grounds aren’t available at all.
Which route you choose matters less than people assume. In many states, fault has no effect on how the court divides money or decides custody. In others, it can shift alimony, protect assets a spouse spent on an affair, or weigh on parenting decisions. The sections below walk through each ground and when the choice actually changes the outcome.
No-Fault Divorce
A no-fault filing requires only that one spouse state the marriage has broken down beyond repair. The exact phrase depends on the state: “irreconcilable differences,” “irretrievable breakdown,” or similar language. No one has to prove cheating, abuse, or any other wrongdoing, and the court doesn’t investigate who caused the problems.
This is the fastest and least expensive path for most couples. There are no witnesses to line up, no private investigators, no detailed testimony about what happened at home. Even spouses with legitimate fault claims often choose no-fault for exactly these reasons. California was the first state to adopt it, in 1970; New York was the last, in 2010.
In pure no-fault states, this is the only option. In the roughly 33 states that offer both tracks, the filing spouse picks.
Adultery
Adultery means a voluntary sexual relationship with someone outside the marriage. You don’t necessarily need direct proof of the act. Courts in many states accept circumstantial evidence that the unfaithful spouse had both the desire and the opportunity: text messages, hotel receipts, witness accounts of romantic behavior.
Filing on adultery grounds puts the accusation in the public court record, which is one reason spouses often choose no-fault even when infidelity ended the marriage. The strategic value of an adultery claim depends on whether your state lets fault affect alimony or property division. In some states it can; in others it makes no financial difference.
Cruelty and Domestic Abuse
Cruelty covers physical violence and severe emotional or psychological abuse. The standard generally requires showing that your spouse’s behavior made it unsafe or genuinely intolerable to continue living together. A single extreme incident can qualify, but courts more often look for a pattern: repeated threats, intimidation, degrading treatment, or physical harm.
Proof usually comes from documentation. Police reports, medical records, protective orders, photographs of injuries, and testimony from witnesses all strengthen a claim. The court looks at both the conduct and its effect, meaning physical injury, emotional distress, or reasonable fear of future violence. This ground carries particular weight in states where fault bears on custody, because evidence of abuse speaks directly to a parent’s fitness.
Desertion and Abandonment
Desertion means one spouse left without the other’s consent and with no intention of returning. The absence usually has to last a continuous period set by state law, often a year or longer. The departure also can’t be justified by the remaining spouse’s own misconduct.
That exception is called constructive desertion. When one spouse makes the home so hostile that the other has no reasonable choice but to leave, courts treat the spouse who stayed as the deserter. Proving it requires showing conditions severe enough that any reasonable person would have left.
Any period of resumed cohabitation during the separation typically resets the clock. Courts look for a clean, uninterrupted break.
Habitual Substance Abuse
Habitual intoxication or drug addiction is a recognized fault ground in many states. Occasional heavy drinking or recreational use isn’t enough. Courts look for a sustained pattern that has fundamentally damaged the marriage, and the filing spouse generally has to show the addiction persisted over time and made the relationship untenable.
Evidence tends to include substance abuse treatment records, arrests for drug or alcohol offenses, testimony from family and friends, and documentation of the effect on the household. Some states frame this ground broadly enough to cover prescription medications and controlled substances, not just alcohol. Where fault affects financial outcomes, it can influence alimony, and because addiction raises direct concerns about parenting, it can affect custody as well.
Felony Conviction and Imprisonment
A spouse’s felony conviction can serve as grounds for divorce in states that allow fault filings. Most require that the conviction occurred during the marriage and that the imprisoned spouse served a minimum period behind bars, commonly between one and three years. The key factor is usually the length of imprisonment, not the nature of the crime.
The conviction generally has to be final, meaning not overturned on appeal, though some states allow the filing even if the conviction is later reversed, as long as the required time was served.
Incurable Mental Illness
A few states allow divorce based on a spouse’s incurable mental illness or permanent mental incapacity. This is one of the least-used grounds because the burden is steep. You typically have to show that your spouse has been confined to a mental health facility for a significant period, often two or three years, and that qualified medical professionals consider recovery unlikely. Expert psychiatric testimony is almost always required.
Some states condition the divorce on the filing spouse making provisions for the ill spouse’s ongoing care.
Living Separate and Apart
Many states recognize a period of physical separation as its own ground for divorce. The couple has to maintain completely separate households for a duration set by state law, and the required periods vary dramatically. Kentucky requires only 60 days. Idaho requires five years. Most states fall between six months and two years.
This ground is more objective than “irreconcilable differences” because it rests on a verifiable fact: the couple lived apart for a specific length of time. Both spouses must show a clear intent to end the marriage throughout the separation. Resuming cohabitation, even briefly, resets the clock in most states. Some states won’t count spouses as living apart if they remain under the same roof, no matter how separately they run their daily lives.
When Fault Actually Affects the Outcome
The practical reason to file on fault grounds, beyond the record of what happened, is money. In some states, proving fault can shift spousal support, property division, or both. In others, fault is legally irrelevant to finances and the only thing at stake is the divorce itself.
Alimony is where fault matters most. A number of states let courts reduce or deny alimony to a spouse who committed adultery, and some allow increased support for the spouse who was wronged. Even in states that generally treat alimony as a purely economic question, courts often make exceptions for egregious misconduct.
Property division is less commonly affected, with one important exception: dissipation of marital assets. When one spouse spent significant marital money on an affair, a gambling habit, or other wasteful purposes, courts can treat those funds as if they still exist when dividing the estate. The spouse who spent the money effectively receives a smaller share of what’s left.
Fault can surface in custody disputes when the misconduct directly affects parenting ability. Evidence of domestic violence, active substance abuse, or criminal behavior weighs heavily. Courts won’t restrict a parent’s custody rights simply because of an affair, but they will act on evidence that a parent’s conduct creates an unsafe environment for children.
Defenses Your Spouse Can Raise
If you file on fault grounds, your spouse isn’t limited to denying the allegations. Several recognized defenses can weaken or defeat a fault claim even when the underlying misconduct actually happened.
Condonation is the most common. It applies when the filing spouse knew about the misconduct and then voluntarily resumed the marital relationship. A spouse who discovers an affair, confronts their partner, and continues living together as a couple has, in the eyes of the court, conditionally forgiven the conduct. The forgiveness is conditional because similar misconduct later can revive the original behavior as grounds.
Recrimination is a defense where the accused spouse argues that the filer committed the same type of misconduct. Historically, if both spouses were guilty of adultery, neither could obtain a divorce. Modern courts take a more practical approach, usually assessing which spouse bears greater responsibility and letting the less culpable spouse proceed. The rise of no-fault has made recrimination largely irrelevant, since either spouse can switch tracks.
Provocation (the misconduct was triggered by the filer’s own behavior) and connivance (the filer facilitated the misconduct) rarely succeed alone but can complicate a case enough to push both parties toward a no-fault resolution.
Residency Requirements and Waiting Periods
Grounds alone aren’t enough. Before any court will accept a divorce case, at least one spouse must have lived in the state for a minimum period. These residency requirements range from no minimum at all in a few states to two years at the longest, with most states falling in the six-week to one-year range. Some states add a county-level requirement on top.
Waiting periods are separate. Many states impose a mandatory delay between the filing date and the date the court can issue a final decree. These cooling-off periods range from 20 days to six months, and some states have none. Filing on fault grounds can sometimes bypass or shorten the waiting period in states that impose one only for no-fault cases, which is an occasionally overlooked advantage of a fault-based filing.