Adultery and concubinage are two distinct criminal offenses under the Revised Penal Code of the Philippines (Act No. 3815), classified as crimes against chastity under Title Eleven. These provisions, originally enacted in 1930 and rooted in the Spanish Penal Code of 1870, remain in force as of December 2025 despite repeated legislative attempts to repeal or reform them. The laws are notoriously gender-asymmetric: adultery punishes married women more severely and requires only a single act of sexual infidelity, while concubinage imposes a higher threshold of proof against married men. Both crimes are private crimes, meaning they can only be prosecuted upon complaint initiated by the offended spouse, and both are subject to condonation, pardon, or subsequent consent.

Adultery (Article 333, Revised Penal Code)

Legal Definition

Adultery is committed by any married woman who shall have sexual intercourse with a man not her husband and by the man who has carnal knowledge of her, knowing her to be married, even if the marriage be subsequently declared void.

Elements of the Crime

For the married woman:

That she is legally married (the marriage must be valid at the time of the sexual intercourse; annulment or declaration of nullity retroacts only for civil purposes but not for criminal liability under this article).
That she has sexual intercourse with a man not her husband.
That the sexual intercourse is voluntary.

For the paramour (the man):

That he has carnal knowledge of a married woman.
That he knows her to be married at the time of the sexual act.

A single act of sexual intercourse is sufficient. No requirement of habituality, scandal, cohabitation, or keeping a mistress exists.

Penalty

Both the guilty wife and the paramour are punished by prisión correccional in its medium and maximum periods (2 years, 4 months and 1 day to 6 years).

Who May File the Complaint

Only the offended husband may file the complaint, and the complaint must include both the wife and the paramour. If the husband files only against the paramour, the case will be dismissed. The husband cannot selectively prosecute.

Pardon and Condonation

Express pardon or condonation by the offended husband extinguishes criminal liability.
Subsequent marriage between the adulterers also extinguishes the crime (Article 89, RPC).
Consent to the sexual act (e.g., open marriage arrangement or prior agreement) is a complete defense.
If the offended spouse continues to cohabit with the guilty spouse knowing of the infidelity, courts have ruled this constitutes implied pardon.

Prescription

The crime prescribes in 10 years (Article 90, RPC).

Concubinage (Article 334, Revised Penal Code)

Legal Definition

Any husband who:

Keeps a mistress in the conjugal dwelling, or
Shall have sexual intercourse, under scandalous circumstances, with a woman who is not his wife, or
Shall cohabit with her in any other place, shall be punished for concubinage.

The mistress/concubine who knowingly consented may also be penalized.

Elements of the Crime

For the husband (any one of the three modes is sufficient):

Keeping a mistress in the conjugal dwelling (the woman lives in the family home with the knowledge and tolerance of the husband).
Having sexual intercourse with a woman not his wife under scandalous circumstances (scandalous circumstances exist when the acts are publicly notorious or openly flaunt disrespect to the marital bond; a single discreet act in a motel is insufficient).
Cohabiting with the woman in any other place (living together as husband and wife in a separate residence).

For the concubine (only if prosecuted): She must have known that the man was married at the time of the acts.

Penalty

Guilty husband: prisión correccional in its minimum and medium periods (6 months and 1 day to 4 years and 1 day).
Guilty concubine (if included in the complaint): destierro (banishment from a certain radius of the wife's residence, usually 25–100 kilometers).

Who May File the Complaint

Only the offended wife may initiate the prosecution. Unlike adultery, she may choose to prosecute only the husband and spare the mistress.

Pardon and Condonation

The same rules on express or implied pardon, subsequent marriage of the offenders, and consent apply as in adultery.

Prescription

10 years.

Key Differences Between Adultery and Concubinage

Aspect	Adultery (Wife)	Concubinage (Husband)
Required act	Single sexual intercourse	One of three specific modes (mistress in conjugal home, scandalous intercourse, or cohabitation)
Proof required	Mere carnal knowledge	Higher: scandal, cohabitation, or keeping in conjugal dwelling
Penalty for guilty spouse	Prisión correccional medium & maximum (up to 6 years)	Prisión correccional minimum & medium (up to 4 years, 1 day)
Penalty for third party	Same as guilty spouse	Only destierro (if prosecuted)
Who must be included in complaint	Both wife and paramour (mandatory)	Wife may prosecute husband alone
Evidentiary difficulty	Relatively easier	Significantly harder

These differences have been repeatedly criticized by the Supreme Court, the Commission on Human Rights, and international bodies (CEDAW Committee) as violative of equal protection and non-discrimination on the basis of sex.

Evidentiary Considerations and Jurisprudence

Direct evidence of sexual intercourse is almost never available. Courts accept strong circumstantial evidence (e.g., love letters, hotel receipts, pregnancy where husband is sterile or impotent, photographs, confessions).
In adultery, pregnancy of the wife during a period when the husband had no access to her is considered the “strongest evidence.”
For concubinage, “scandalous circumstances” has been interpreted to require public notoriety (People v. Santos, 1937; People v. Pitoc, 1940).
Cohabitation means living together as husband and wife, not merely occasional visits.
Text messages, Facebook posts, and CCTV footage are now commonly admitted as evidence.
The Supreme Court has ruled that a husband who tolerates his wife’s lover living in the family home may himself be guilty of concubinage by analogy (though rare).

Civil Consequences

Ground for legal separation (Article 55, Family Code) – either adultery or concubinage.
Forfeiture of presumptive legitimes of guilty spouse in favor of innocent spouse and children (Article 63, Family Code).
Disqualification from inheriting from the innocent spouse intestate.
Loss of custody over minor children if the court finds it is in the children’s best interest.
Psychological violence under Republic Act No. 9262 (Anti-VAWC Law) – repeated infidelity may be considered psychological violence, giving the wife additional civil and criminal remedies (protection orders, damages).

Current Status and Reform Efforts

As of December 2025, Articles 333 and 334 remain in force. Multiple bills seeking to decriminalize adultery and concubinage or replace them with a gender-neutral “marital infidelity” law have been filed in every Congress since the 1990s (notably the “Anti-Marital Infidelity Act” proposals and the Divorce Bill discussions). None have passed.

The Supreme Court has repeatedly urged Congress to repeal or amend these provisions, calling them “archaic” and “discriminatory” (see Disini v. Secretary of Justice, 2014, on related cybercrime provisions; and separate opinions in Estrada v. Escritor, 2003/2006).

The Philippines remains one of the few countries in the world that still criminalizes adultery and concubinage as distinct offenses.

Conclusion

Adultery and concubinage represent a vestige of colonial morality that treats marital infidelity differently depending on the sex of the offender. While they continue to be invoked (particularly adultery cases in lower courts), successful convictions are rare due to evidentiary difficulties, cultural reluctance to publicize family shame, and frequent condonation. In practice, most aggrieved spouses now prefer to file psychological violence cases under RA 9262 or seek legal separation/annulment rather than pursue these criminal actions. Until Congress acts, however, these gender-discriminatory provisions remain part of Philippine positive law.