Below is a comprehensive discussion of the crime of adultery as it exists under Philippine law. This article is for general informational purposes only and does not constitute legal advice. If you need guidance specific to your case, please consult a licensed Philippine attorney.

1. Legal Basis

The primary legal provision governing the crime of adultery in the Philippines is Article 333 of the Revised Penal Code (RPC). This law prescribes the definition, elements, penalty, and other key points regarding the prosecution of adultery.

Under Philippine law, the crime of “adultery” only applies to a married woman who engages in sexual relations with a man who is not her husband. Meanwhile, a married man who engages in sexual relations outside marriage may be charged with concubinage under Article 334 of the RPC if certain conditions are met. Although both crimes arise from marital infidelity, they are treated distinctly under the law.

2. Definition and Elements of Adultery

2.1 Definition

Under Article 333 of the Revised Penal Code, adultery is committed by any married woman who has sexual intercourse with a man not her husband, and by the man who has carnal knowledge of her, knowing that she is married—even if the marriage is later declared void.

2.2 Elements of Adultery

To prove adultery in court, the prosecution must establish the following elements:

The woman is married.
There must be a valid and subsisting marriage at the time of the alleged adulterous act.
Sexual intercourse occurred.
There must be evidence of actual carnal knowledge between the married woman and the alleged male partner.
Knowledge of the woman’s marital status (for the male partner).
The man, to be liable, must be aware or must have the means to know that the woman is married.

3. Who May File the Case and Its Nature as a Private Crime

3.1 Exclusive Right of the Offended Spouse

Adultery is classified as a private crime. This means that only the offended husband (i.e., the lawful spouse of the accused wife) can initiate the criminal complaint. The State (public prosecutor) will generally not proceed with an adultery case unless the offended husband has filed a formal complaint.

3.2 Indispensable Party Requirement

When the offended husband files a criminal case for adultery, both the wife and the alleged male partner must be included as accused. The husband cannot choose to proceed against only one of them. Failure to include both parties can be grounds for the dismissal of the case.

3.3 No Prosecution If There Was Consent or Pardon

The law also disallows prosecution under the following scenarios:

Consent: The offended husband explicitly or implicitly agreed to the adulterous relationship.
Pardon: The offended husband forgave the adulterous act(s). Pardon can be express (a written or verbal statement of forgiveness) or implied (by resuming cohabitation with knowledge of the infidelity, for example).

If consent or pardon is proven, this constitutes a bar to criminal prosecution.

4. Penalties for Adultery

4.1 Imprisonment

Under Article 333 of the Revised Penal Code, adultery is punishable by prisión correccional in its medium and maximum periods. In terms of duration, prisión correccional ranges from 6 months and 1 day to 6 years, divided into three periods:

Minimum Period: 6 months and 1 day to 2 years and 4 months
Medium Period: 2 years, 4 months, and 1 day to 4 years and 2 months
Maximum Period: 4 years, 2 months, and 1 day to 6 years

The court has discretion to fix the specific duration of the penalty within the prescribed range, taking into account any mitigating or aggravating circumstances.

4.2 Equal Penalty for Both Accused

Both the married woman and her male partner (if proven guilty) are punished by the same duration of imprisonment. However, in actual practice, mitigating or aggravating circumstances (e.g., offender’s age, prior convictions, or means of the commission of the offense) may affect how the penalty is applied to each accused.

5. Evidentiary Considerations

5.1 Proof of Sexual Intercourse

In adultery cases, direct evidence of sexual intercourse (e.g., being caught in the act) is often difficult to obtain. The courts may rely on circumstantial evidence to infer that carnal knowledge occurred. Examples of strong circumstantial evidence include:

Correspondence or messages clearly demonstrating an adulterous relationship.
Eyewitness accounts of the accused entering a private place under suspicious circumstances, staying overnight, etc.
Photographs or videos (though authenticity must be verified).

The quantum of proof required is proof beyond reasonable doubt, as in all criminal cases.

5.2 Testimony of Witnesses

Given that adultery is considered a private crime, direct testimony from third parties is often limited. The offended husband’s testimony, if credible and corroborated by other evidence, can be key. Private detectives or eyewitnesses could also testify if the circumstances allow.

6. Procedure for Filing a Criminal Case

6.1 Steps for the Offended Spouse

Consult a Lawyer
The offended husband typically consults an attorney for legal advice on gathering evidence and deciding whether there is a prima facie case.
Affidavit-Complaint
The offended husband executes a complaint affidavit detailing the facts constituting adultery. This affidavit is filed with the Office of the City or Provincial Prosecutor.
Prosecutor’s Preliminary Investigation
The prosecutor conducts a preliminary investigation to determine if there is probable cause to file the case in court.
Filing of Information in Court
If the prosecutor finds probable cause, an Information for adultery is filed in the Regional Trial Court, where the formal trial commences.

6.2 Prescription Period

Crimes of adultery prescribe in 5 years from the date the offended spouse actually discovers the adulterous act. If the offended husband takes no action within 5 years of discovery, the State can no longer prosecute the offense.

7. Defenses and Possible Outcomes

7.1 Common Defenses for the Accused

No Valid Marriage
Proving that there was no valid marriage in the first place (e.g., the alleged marriage was annulled or void ab initio) can negate one of the elements of adultery.
Lack of Sexual Intercourse
Denying that the alleged act occurred and challenging the adequacy of evidence.
Lack of Knowledge of the Marriage (for the male partner)
Arguing that the male partner did not know—or had no reasonable means of knowing—that the woman was married.
Consent or Pardon
The accused can show that the offended husband consented to or pardoned the act, thereby barring prosecution.

7.2 Outcome of Conviction

If the court finds both accused guilty beyond reasonable doubt, each is penalized with prisión correccional within the range set by the Revised Penal Code, subject to the court’s discretion based on any mitigating or aggravating circumstances.

8. Distinction from Concubinage (for Married Men)

Although the question focuses specifically on “adultery,” it is important to highlight that married men do not commit “adultery” under Philippine law; rather, they may commit concubinage under Article 334 of the RPC if they:

Keep a mistress in the conjugal dwelling.
Have sexual intercourse under scandalous circumstances with a woman who is not their wife.
Cohabit with her in any other place.

For the wife to file a criminal case for concubinage, similar private crime rules apply (i.e., only the offended wife can initiate the complaint, both the husband and the concubine must be charged, etc.). However, the penalty structure and evidentiary requirements differ from adultery.

9. Civil Aspects and Marital Remedies

9.1 Civil Liabilities

A criminal conviction for adultery does not automatically give rise to civil indemnities akin to damages in other criminal cases, but the offended spouse may seek damages in a separate civil action if justified (e.g., mental anguish, moral damages). Legal advice is essential to navigate civil remedies.

9.2 Marital Remedies

The discovery of adultery is frequently cited as a ground for legal separation under the Family Code. However, it is not in itself a ground for an annulment of marriage unless specific legal grounds for annulment exist (e.g., psychological incapacity under Article 36 of the Family Code, fraud, etc.).

10. Key Takeaways

Adultery is a private crime that can only be prosecuted upon the complaint of the offended husband.
Both the married woman and her male partner must be included as accused in the complaint.
The penalty is prisión correccional in its medium and maximum periods (ranging from over 2 years to up to 6 years).
Consent or pardon by the husband bars criminal prosecution.
Evidence of sexual intercourse—whether direct or circumstantial—must meet the standard of proof beyond reasonable doubt.
The prescriptive period is 5 years from the date the offended husband discovered the adultery.
A separate civil action or legal separation case may be pursued alongside or independently of any criminal complaint for adultery.

11. Conclusion

Criminal cases for adultery in the Philippines hinge on strict legal and evidentiary requirements unique to this private crime. The law aims to protect the sanctity of marriage but also guards against misuse of the criminal process, requiring that the offended spouse personally initiate and substantiate the charges. Because of the complexity of the legal and procedural issues involved, anyone contemplating filing or defending an adultery charge is strongly advised to seek professional legal counsel.

Disclaimer: This article is for informational purposes only and does not substitute for professional legal advice. Laws and their interpretations may change over time, and individual circumstances can significantly affect legal outcomes. If you need guidance or representation in a specific matter, consult a qualified Philippine attorney.