1. Statutory Foundations

Crime	Codal Provision (Revised Penal Code, RPC)	Who is Liable	Penalty
Adultery	Art. 333	A married woman and her sexual partner (regardless of the latter’s civil status)	Prisión correccional in its medium and maximum periods (2 yrs-4 mos-1 day to 6 yrs) for each act
Concubinage	Art. 334	A married man and his concubine (the woman must “knowingly” cohabit with or be kept by the man)	Husband: Prisión correccional in its minimum to medium periods (6 mos-1 day to 4 yrs-2 mos). Concubine: Destierro (banishment) for the same duration

Key take-away: Both are still crimes in the Philippines. They are classified as private crimes—the State will not prosecute unless the offended spouse (the complainant) takes the first step.

2. Elements You Must Prove

A. Adultery

Existing valid marriage of the offended spouse.
Sexual intercourse between the wife and a man not her husband.
Knowledge on the part of the man that the woman is married (express or implied).
Each act of intercourse constitutes a separate count—so dates matter.

B. Concubinage

Existing valid marriage of the offended spouse.
Any of the following circumstances:
- (a) The husband keeps a mistress in the conjugal dwelling; or
- (b) The husband cohabits with a woman in any other place; or
- (c) The husband has sexual intercourse with a woman under scandalous circumstances.
Knowledge and participation of the concubine.
Proof threshold is higher than adultery; mere occasional trysts usually fail to constitute concubinage.

3. Who May File, When, and Where

Requirement	Explanation
Complainant	Only the offended spouse may initiate the case. If he or she dies before filing, the right evaporates.
Indispensable Parties	The complaint must include both guilty parties (your spouse and the third party) if they are alive; omitting either is fatal.
Consent or Pardon	If prior to filing: bar to prosecution. If given after filing: a ground to extinguish criminal liability. Consent = before the affair; Pardon = after discovery.
Prescription	20 years from the date of the last adulterous/concubinous act.
Venue / Court	Metropolitan/City/Municipal Trial Court (penalty ≤ 6 yrs). File the criminal Information in the city/municipality where any element of the crime occurred (usually where the intercourse or cohabitation happened).

4. Step-by-Step Filing Procedure

Gather Evidence
- Chat logs, hotel receipts, love letters, birth certificates of illegitimate children, eyewitness affidavits, photos/videos, GPS-tagged posts, etc.
- For adultery, you need to show sexual intercourse—circumstantial evidence is allowed but must strongly point to that fact.
- For concubinage, focus on cohabitation or scandal—utility bills at a shared address, lease contracts, “live-in” social-media posts, or neighbors’ testimonies help.
Draft a Verified Affidavit-Complaint
- State complete facts, dates, places, and attach supporting documents.
- Sworn before a prosecutor or notary.
File with the Office of the City/Municipal Prosecutor (OCP/OMBP)
- Pay docket fees (minimal).
- The prosecutor issues subpoenas to respondents.
Preliminary Investigation
- Submission of counter-affidavits; possibility of clarificatory hearing.
- Prosecutor’s Resolution: (a) file information in court, or (b) dismiss.
- Aggrieved party may move for reconsideration, then elevate to the Department of Justice via petition for review.
Filing of Information in Court
- Arraignment, pre-trial, trial on the merits.
- Mediation or plea bargaining is rare (being a private crime, but mediation is not favored).
Judgment & Possible Remedies
- Conviction requires proof beyond reasonable doubt.
- Post-judgment motions: Motion for Reconsideration → Appeal to the Regional Trial Court (appellate jurisdiction over MTC decisions) → Court of Appeals → Supreme Court by petition for review on certiorari.

5. Civil & Ancillary Consequences

Civil Indemnity & Damages – The court may award moral and exemplary damages under Art. 100, RPC, or in a separate civil action.
Forfeiture of Conjugal Share – Art. 43(2), Family Code: a spouse in concubinage/adultery forfeits share in net profits of the absolute community or conjugal partnership upon legal separation.
Implications for Annulment / Nullity / Legal Separation – While adultery or concubinage per se is a ground for legal separation, criminal conviction is not required; proof for civil cases need only be preponderance of evidence.
Violence Against Women & Children (VAWC) – If the affair causes psychological violence on the wife or a common-law partner, the same acts may simultaneously constitute VAWC under R.A. 9262, carrying heavier penalties.

6. Common Defenses

Consent or Pardon – Express or implied. Save screenshots that show you were forgiven.
Marriage Void from the Start – If the complainant’s own marriage is void and the respondent honestly believed so, courts may acquit for lack of requisite element (valid existing marriage).
Impossible Crime / Mistake of Fact – Extremely rare; e.g., if medical evidence shows intercourse impossible.
Failure to Join Necessary Party – Complaint against one defendant only.
Alibi & Lack of Opportunity – In adultery cases, rebut circumstantial links.
Questioning Authorship/Authenticity of Digital Evidence – Challenge metadata, chain of custody, or invoke Data Privacy Act violations.

7. Evidentiary Tips

Type of Evidence	Recommended Collection Hints
Digital	Make forensic copies (hash-verified) of chats & emails; subpoena phone records if needed.
Documents	Authenticate hotel receipts via the issuing establishment’s keeper of records.
Witnesses	Neighbors, security guards, or children’s nannies who can testify on cohabitation.
Expert Testimony	For DNA tests proving paternity of an illegitimate child born during cohabitation.

8. Gender-Bias Issues & Reform Initiatives

Asymmetrical Standards. Adultery punishes all sex outside marriage by wives; concubinage punishes only narrow categories of the husband’s infidelity.
Pending House & Senate Bills (various Congresses) have sought to:
- Decriminalize both offenses; or
- Harmonize penalties regardless of sex; or
- Convert them into civil grounds for damages/divorce.
Philippine Supreme Court has repeatedly urged Congress—most recently in People v. Jumawan (2014)—to revisit the “archaic double standard.”

9. Practical & Ethical Considerations

Emotional Cost vs. Benefit. Criminal cases are public records; mediation or civil action may offer quieter closure.
Time & Money. Adultery/concubinage trials can drag 3-7 years; weigh personal objectives.
Safety Planning. If violence is involved, consider VAWC protection orders or barangay-level BPOs.
Parallel Remedies. You can simultaneously seek:
- Nullity or annulment of marriage (civil);
- Legal separation with forfeiture;
- VAWC criminal case;
- Support and custody cases.
Data Privacy. Posting “proof” on social media can expose you to libel or privacy suits. Share only with counsel and prosecutors.

10. Quick Reference Checklist

✅ Valid marriage exists.
✅ Both offenders alive and named.
✅ No prior consent/pardon.
✅ Evidence secured & preserved.
✅ Affidavit-complaint prepared and notarized.
✅ Filed with correct OCP/MTC.
✅ Act(s) within 20-year prescriptive period.

Final Word

Filing an adultery or concubinage complaint is not merely a legal maneuver; it is a deeply personal, sometimes traumatic process with lasting ramifications—emotional, financial, and even spiritual. Consult a trusted Philippine lawyer before taking any irrevocable steps, explore non-litigious options where possible, and make sure your decision aligns with your long-term well-being.

(This article is for informational purposes only and does not constitute legal advice. Laws and jurisprudence evolve; always verify with updated sources or professional counsel.)