No, adultery is not a crime in California. Nothing in the California Penal Code makes an extramarital affair a criminal offense, and no one can be arrested, charged, fined, or jailed for cheating on a spouse. The consequences of infidelity in California are financial and personal, not criminal — with one significant exception for members of the military, who answer to federal law no matter where they live.
What California Law Actually Says About Cheating
California has never criminalized adultery in its modern code. A handful of other states still keep adultery statutes on the books, but prosecutions under them are rare, and California simply has no equivalent provision at all. There is no fine, no probation, no jail exposure for a civilian who has an affair, regardless of the circumstances or who finds out.
The confusion usually comes from mixing moral weight with legal weight. In California, the legal system treats infidelity as a private matter between spouses. It only becomes legally relevant when it touches money or the welfare of a child, and even then it enters the case through the back door rather than as “adultery.”
Affairs in a California Divorce
California is a no-fault divorce state. The only ground needed to end a marriage is “irreconcilable differences” that have caused an irreparable breakdown, or permanent incapacity to make decisions.1California Legislative Information. California Family Code 2310 – Dissolution of the Marriage or Legal Separation of the Parties A spouse filing for divorce does not have to mention an affair, and a judge will grant the dissolution whether one happened or not. Evidence of cheating cannot be used to block or delay the divorce itself.
Spousal Support
Spousal support in California is set from a statutory list of financial and practical factors: each spouse’s earning capacity, the standard of living during the marriage, length of the marriage, age and health, and the paying spouse’s ability to afford support, among others.2California Legislative Information. California Family Code 4320 – Spousal Support Marital misconduct is not on the list. The one form of misconduct that explicitly affects support is domestic violence, where a criminal conviction can reduce or eliminate an award. Cheating, standing alone, does not raise or lower support. A judge who personally sympathizes with the wronged spouse still has no legal basis to punish the affair through the support order.
Community Property and Money Spent on the Affair
California’s community property system splits assets and debts acquired during the marriage equally.3California Courts. Property and Debts in a Divorce An affair does not shift that 50/50 division on its own. What can shift it is dissipation — community money spent on the affair itself.
Each spouse owes the other a fiduciary duty in managing community property.4California Legislative Information. California Family Code 1100 – Management and Control of Community Assets When one spouse spends community funds on an affair partner — hotels, gifts, trips, rent, dinners — that spending breaches the duty and impairs the other spouse’s half-interest. The wronged spouse can bring a claim for breach of fiduciary duty, and the court can rebalance the property division or award compensation.5California Legislative Information. California Family Code 1101 – Breach of Fiduciary Duty Success turns on documentation: credit card statements, bank transfers, receipts, cash withdrawals. The court cares what happened to the money, not the details of the relationship.
Child Custody
Custody follows the best-interest-of-the-child standard, which looks at the child’s health and safety, any history of abuse, substance abuse, and the nature and amount of contact with each parent.6California Legislative Information. California Family Code 3011 – Best Interests of the Child A parent’s sexual conduct outside the marriage is not a factor. An affair matters to custody only if the surrounding behavior harmed the child — for example, leaving a young child unsupervised to meet a partner. Even then, the court treats it as neglect, not adultery.
You Cannot Sue the Other Person
Some states still let a spouse sue their partner’s lover under old doctrines called “alienation of affection” and “criminal conversation.” California does not. State law explicitly abolishes any cause of action for alienation of affection, criminal conversation, or seduction of a person over the age of consent.7California Legislative Information. California Civil Code 43.5 There is no civil claim available against your spouse’s affair partner for the affair itself, for emotional distress caused by it, or for the end of the marriage.
What About Infidelity Clauses in a Prenup?
California’s prenuptial agreement statute lets couples contract broadly on property, financial obligations, and “any other matter, including their personal rights and obligations, not in violation of public policy or a statute imposing a criminal penalty.”8California Legislative Information. California Family Code 1612 – Premarital Agreements On its face, that language seems to leave room for an infidelity penalty clause.
In practice, California courts generally refuse to enforce “lifestyle clauses” that impose financial penalties for cheating. Judges tend to view them as inconsistent with the state’s choice not to treat adultery as legally relevant to divorce. A clause that doubles one spouse’s property share if the other has an affair is unlikely to hold up, and anyone considering one should get a family law attorney’s read before relying on it.
The Military Exception
The one place where an affair can actually be a crime for someone living in California is the armed forces. Under the Uniform Code of Military Justice, extramarital sexual conduct can be prosecuted under Article 134, the general article covering conduct prejudicial to good order and discipline or that brings discredit on the armed forces.9Office of the Law Revision Counsel. 10 USC 934 – Art. 134 General Article This applies to service members regardless of the state they are stationed in.
A military adultery case requires proof of a sexual act, that one of the parties was married to someone else at the time, and that the conduct actually harmed military discipline or reputation.10United States Court of Appeals for the Armed Forces. Core Criminal Law Subjects – Crimes – Article 134 Adultery That last element matters: the affair alone is not enough; the government has to show real impact, with factors like the ranks involved and whether a unit was disrupted all in play.
The exposure at court-martial is serious. The maximum punishment under the Manual for Courts-Martial includes a dishonorable discharge, forfeiture of all pay and allowances, and up to one year of confinement. Short of a court-martial, a service member may still face nonjudicial punishment or adverse administrative action that can end a career.11The United States Army. Legal Separation, Adultery and the UCMJ For a military family in California, the same conduct that carries no criminal consequences for the civilian spouse can mean confinement and discharge for the service member.