Adultery in a Missouri divorce can shape the outcome in three concrete ways: it can serve as the ground that pushes a dissolution through over a spouse’s objection, it can shift how a judge decides spousal maintenance and property division, and it can strip a spouse of inheritance rights if a death occurs before the divorce is final. What it generally does not do is decide custody, and it does not entitle a faithful spouse to punish the other through the property split.
Adultery as a Ground for Divorce
Missouri is commonly described as a no-fault state, and for most divorces that description holds. If both spouses agree the marriage is irretrievably broken, or one says so without objection from the other, the court can dissolve the marriage without anyone proving wrongdoing.
The picture changes when one spouse denies the marriage is irretrievably broken. Section 452.320 then requires the petitioning spouse to prove at least one specific ground, and adultery leads the list. The petitioner must show that the other spouse committed adultery and that the petitioner finds it intolerable to continue living with them. The other grounds are behavior making continued cohabitation unreasonable, abandonment for at least six months, twelve months of separation by mutual consent, and twenty-four months of separation without consent.1Missouri Revisor of Statutes. Missouri Code 452.320 – Dissolution, Findings Required For
The practical effect: if your spouse resists the divorce, adultery can be the mechanism that gets it granted anyway.
How Adultery Affects Spousal Maintenance
Maintenance (Missouri’s term for alimony) is where adultery tends to carry the most weight. Under Section 452.335, a court can award maintenance only if the requesting spouse lacks enough property to meet reasonable needs and cannot support themselves through appropriate employment. Once that threshold is cleared, the court sets amount and duration based on a list of factors that includes “the conduct of the parties during the marriage.”2Missouri Revisor of Statutes. Missouri Revised Statutes 452.335 – Maintenance Order, Findings Required For
Conduct is the statutory hook. A judge might reduce maintenance for a spouse who carried on an affair, or increase it for the faithful spouse. But conduct is one of ten factors the statute lists. Length of the marriage, each spouse’s earning capacity, the standard of living during the marriage, and each spouse’s physical and emotional condition all sit alongside it. Adultery alone rarely drives the entire maintenance decision.
Maintenance orders can be either modifiable or nonmodifiable. A modifiable order can be decreased, increased, or terminated based on a substantial change in circumstances before the termination date.2Missouri Revisor of Statutes. Missouri Revised Statutes 452.335 – Maintenance Order, Findings Required For If new evidence of adultery surfaces later, or finances shift, modification may be possible.
How Adultery Affects Property Division
Missouri divides marital property under equitable distribution: fair, not necessarily equal. Section 452.330 tells courts to divide marital property and debts “in such proportions as the court deems just” after weighing several factors, one of which is again “the conduct of the parties during the marriage.”3Missouri Revisor of Statutes. Missouri Code 452.330 – Disposition of Property and Debts, Factors to Be Considered
Missouri appellate decisions have set boundaries on how far conduct can move the division. In Butcher v. Butcher, the court held that “conduct” covers general conduct during the marriage, not just financial misdeeds. In Marriage of Schulte, the court acknowledged a wife’s misconduct should be considered but said it did not deprive her of the right to share equitably in marital property, particularly given a nineteen-year marriage where the misconduct began late. In Arp v. Arp, the court emphasized that the statute requires a “just” division, not an equal one, even where a spouse engaged in marital misconduct.3Missouri Revisor of Statutes. Missouri Code 452.330 – Disposition of Property and Debts, Factors to Be Considered
Adultery can tilt the split. It will not strip the cheating spouse of a share as punishment. Economic circumstances, contributions to marital property (including homemaking), and custodial arrangements all factor in alongside conduct.
Dissipation of Marital Assets
Where adultery hits property division hardest is when marital money was spent on the affair. Hotels, dinners, gifts, trips, dating site memberships — courts can treat this as dissipation of marital assets. The court may credit those wasted funds back to the marital estate so the faithful spouse is not effectively subsidizing the affair. If you suspect significant marital funds went to an extramarital relationship, documentation from bank statements and credit card records strengthens the argument considerably.
How Adultery Affects Child Custody
Adultery has far less influence on custody than most people assume. Section 452.375 directs courts to decide custody based on the child’s best interests. The statutory factors focus on the child’s relationships, each parent’s willingness to foster contact with the other parent, the child’s adjustment to home and school, and the mental and physical health of everyone involved.4Missouri Revisor of Statutes. Missouri Code 452.375 – Custody, Best Interests of Child
“Conduct of the parties during the marriage” does not appear in the custody factors the way it appears in the maintenance and property statutes. Missouri also creates a rebuttable presumption in favor of equal or approximately equal parenting time. A parent’s affair, by itself, does not overcome that presumption.4Missouri Revisor of Statutes. Missouri Code 452.375 – Custody, Best Interests of Child
The exception is when the affair directly harmed the child. Exposing the child to inappropriate situations, introducing an unstable or dangerous partner into the household, or neglecting parenting responsibilities while pursuing the relationship can become relevant under the health, safety, and adjustment factors. Judges care about the child’s wellbeing, not about punishing a parent’s choices. Trying to weaponize adultery in a custody fight without showing actual harm to the child rarely lands.
Loss of Inheritance Rights Before the Divorce Is Final
This is the consequence most people miss. Under Section 474.140, a spouse who voluntarily leaves and continues living with an adulterer, or who abandons the other spouse without reasonable cause and lives apart for the year before that spouse’s death, or who continuously lives with another person in a state of adultery, permanently loses inheritance rights, homestead allowance, exempt property, and any other statutory allowance from the deceased spouse’s estate.5Missouri Revisor of Statutes. Missouri Code 474.140 – Inheritance and Statutory Rights Barred on Misconduct of Spouse
The only way to restore those rights is voluntary reconciliation and a return to living together. If spouses have separated and one is living with a new partner but the divorce is not finalized, the exposure runs beyond the divorce courtroom. Death during that gap can trigger the statute.
Proving Adultery
The spouse alleging adultery carries the burden of proof. Direct proof is rare, so courts routinely rely on circumstantial evidence. The kinds of evidence that tend to carry weight:
- Text messages, emails, social media messages, and call logs showing an intimate or romantic relationship
- Credit card statements, bank records, and receipts showing spending on hotels, restaurants, gifts, or dating services that cannot be explained
- Photographs or video showing the accused spouse with another person in compromising circumstances
- Testimony from people who observed the relationship firsthand
- Admissions by the accused spouse, verbal, written, or electronic
Baseless accusations backfire. Accusing your spouse of adultery without evidence damages your credibility with the judge on every other issue in the case. Courts also disfavor evidence obtained illegally, such as hacking accounts or unlawfully recording conversations. Missouri is a one-party consent state for recordings, meaning you may record a conversation you are part of, but you cannot record conversations between your spouse and someone else without their knowledge.
Defenses Against Adultery Allegations
The most direct defense is challenging the evidence itself: whether messages are authentic, whether financial records show what’s claimed, whether witnesses are credible or biased. Two doctrines also apply.
Condonation
Condonation applies where the accusing spouse knew about the adultery and forgave it, typically by resuming the marital relationship. A spouse who discovered an affair, chose to continue the marriage, and then tried to use that same affair in divorce proceedings can be met with a condonation argument. Condonation can itself be undone if the adulterous spouse resumes the affair or commits new acts of infidelity after being forgiven.
Recrimination
Recrimination applies when the accusing spouse also engaged in adultery. If both spouses had affairs, the court may give less weight to either side’s adultery allegations when making decisions about maintenance and property.
Attorneys also sometimes place the adultery in the context of a marriage that had effectively ended earlier, framing the affair as a symptom rather than a cause. This does not erase the adultery, but it can reduce the weight a judge gives it relative to other factors.
Costs and the Case for Settling
Divorces involving adultery allegations cost more than uncontested dissolutions. The initial filing fee is modest — around $150 in many counties — but attorney fees escalate quickly when adultery has to be investigated, documented, and argued. Private investigator rates typically run from $50 to $125 per hour depending on experience and the complexity of the surveillance. Mediator rates run from $100 to several hundred dollars per hour, still generally far less than a contested trial.
Missouri courts encourage mediation in contested family cases. A neutral mediator can facilitate discussions on maintenance, custody, and property without the adversarial dynamics of a courtroom, and mediation does not require either party to concede fault. Contested trials also put the details of the affair into the public record, which gives the accused spouse an incentive to settle and gives the accusing spouse a guaranteed outcome instead of a judge’s discretion.
Before pursuing adultery as a litigation strategy, have a direct conversation with your attorney about whether the evidence is strong enough to meaningfully change the outcome, and whether the likely financial benefit justifies the cost of proving it. In many cases the answer shapes not just the strategy but whether the case goes to trial at all.