1) The crime of adultery in Philippine law

Adultery is a crime under the Revised Penal Code (RPC). It is committed by a married woman who has sexual intercourse with a man not her husband, and by the man (paramour) who has carnal knowledge of her knowing she is married.

It is distinct from:

Concubinage (the parallel offense for a married man under the RPC), and
Civil actions like annulment, legal separation, or damages.

2) Who are the accused in an adultery case?

Adultery is a dual-accused offense in practice:

The wife (must be legally married at the time of the act); and
The paramour (must have knowledge of her marriage).

It is possible in theory to have a case proceed against only one accused if the other cannot be charged (e.g., unknown identity, at large, dead), but adultery is generally treated as a crime involving both participants and complaints are commonly filed against both.

3) Elements of adultery

To convict, the prosecution must prove beyond reasonable doubt:

A. For the wife

She is married; and
She had sexual intercourse with a man not her husband.

B. For the paramour

He had sexual intercourse with the woman;
The woman is married; and
He knew she was married.

Sexual intercourse is essential. Mere intimacy, dating, hotel stays, sweet messages, or kissing—without proof of carnal knowledge—will not meet the strict element, though they may be used as circumstantial evidence depending on the case.

4) Key characteristics of adultery cases

A. Each act can be charged

Each act of sexual intercourse may be treated as a separate offense, though charging is often framed around a period and place and the evidence dictates how many counts are viable.

B. It’s a “private crime”

Adultery is generally treated as a private offense in the sense that prosecution typically requires a complaint by the offended spouse (the husband, in adultery). It is not ordinarily prosecuted on a mere police report or third-party complaint.

C. The offended spouse’s role is central

Without the offended spouse’s complaint (and consistent participation), the case typically cannot move forward properly.

5) Who can file, and where to file?

A. Who can file the criminal complaint?

The offended spouse—in adultery, the husband—is the proper complainant. Practical standing is anchored on the marital relationship and being the party offended by the infidelity.

B. Where is it filed?

Usually the case begins with a criminal complaint filed with the Office of the City/Provincial Prosecutor for preliminary investigation (if required), then potentially an Information is filed in court.

Venue is generally where the offense occurred (place of sexual intercourse). In practice, venue is often built around where the couple’s acts happened (residence/hotel/condo), supported by evidence.

6) Evidence: what typically proves (or fails to prove) adultery

A. Direct evidence is rare

Few cases have direct testimony of the act itself. Most are built using circumstantial evidence, which can still convict if it meets the standard: the circumstances are consistent with guilt and exclude reasonable doubt.

B. Common evidence used

Hotel/condo logs, CCTV, keycard records, receipts (with identification value)
Witness testimony on cohabitation/overnights, exclusive presence, being seen entering and leaving together at times consistent with intercourse
Admissions (texts, chats, written confessions), especially when clear, voluntary, and properly authenticated
Photos/videos (with authentication and lawful acquisition issues)
Birth of a child plus proof linking paternity and timing (not automatic proof of intercourse for the charged dates, but can be powerful context evidence)

C. Evidence that is often insufficient by itself

Flirtatious chats without stronger corroboration
“Seen together” in public places
“Dating” alone without proof of sexual intercourse
Suspicion or hearsay (“someone told me they slept together”)

D. Evidence pitfalls

Illegally obtained evidence (e.g., hacking accounts, unlawful interception) can be challenged and may be excluded and can expose the gatherer to liability.
Authentication issues: screenshots and printouts must be tied to the parties and integrity of the data must be established.
Weak identification: hotel receipts without linking the name to the person, or CCTV without clarity.

7) Penalty

Adultery is punishable by prisión correccional in its medium and maximum periods (a range of imprisonment within prisión correccional). The paramour and the wife are punished similarly if convicted.

Penalty application (exact duration) depends on:

The court’s findings,
Mitigating/aggravating circumstances (if any),
The Indeterminate Sentence Law (when applicable).

8) Prescription (time limit to file)

Crimes have prescriptive periods (time limits) depending on the penalty classification. Adultery has a finite window to commence prosecution. Computation can be legally nuanced (e.g., from commission, from discovery in some contexts, and procedural interruptions), so timing matters heavily in practice.

9) Relationship to concubinage (and why this matters)

Adultery and concubinage are different crimes with different elements:

Adultery (wife)

Requires sexual intercourse with a man not her husband.
Paramour liable if he knew she was married.

Concubinage (husband)

Committed by a married man by:

Keeping a mistress in the conjugal dwelling, or
Having sexual intercourse under scandalous circumstances, or
Cohabiting with her in any other place.

Because concubinage has additional conditions, it can be harder to prove than adultery, and the penalties differ.

10) Defenses commonly raised

A. Denial and failure of proof of sexual intercourse

The strongest defense often is that the evidence does not prove carnal knowledge beyond reasonable doubt.

B. Lack of knowledge (for the paramour)

A paramour may argue he did not know the woman was married. This defense depends on the facts:

Did she present herself as single?
Was there notice (public posts, admissions, mutual friends, living situation)?
Were there circumstances making knowledge obvious?

C. No valid marriage (or marriage void)

If the marriage is void (e.g., void ab initio), the “married woman” element is undermined. The viability of this defense depends on whether a competent determination of marital status is established and how courts treat the proof of marriage in the criminal case.

D. Identity / alibi issues

Where the evidence is receipts/CCTV, accused may challenge identity: “That’s not me,” “The account/card was used by someone else,” etc.

E. Procedural defenses

Defects in complaint or Information
Improper venue/jurisdiction
Lack of authority of complainant (not the offended spouse)
Due process issues in preliminary investigation

11) The special rule on pardon / consent and its effect

Adultery (and concubinage) have special dynamics involving the offended spouse:

A. Consent or pardon can be case-dispositive

In many adultery/concubinage scenarios, pardon by the offended spouse can bar or terminate prosecution, but it is not casual forgiveness—it typically requires conditions recognized by law and jurisprudence, and the timing and form matter.

B. Pardon must often cover both offenders

As a rule in these offenses, pardon has to be consistent: if the offended spouse forgives one participant while still pursuing the other, courts often scrutinize this because the acts are intertwined.

C. Condonation in practice

Reconciliation, resumption of marital relations after knowledge of the affair, or explicit forgiveness can be argued as condonation/pardon depending on facts. This is highly fact-sensitive.

12) Procedural flow of a typical adultery case

Gather evidence (lawfully) and document timeline.
File complaint-affidavit with the prosecutor (with attachments).
Preliminary investigation: respondents submit counter-affidavits; clarificatory hearings may occur.
Prosecutor issues a resolution: dismissal or finding of probable cause.
If probable cause: Information filed in court; warrants/summons issued.
Arraignment, pre-trial, then trial.
Judgment: conviction/acquittal; civil liabilities may also be addressed.

13) Civil and family-law consequences alongside the criminal case

An adultery case is criminal, but it often triggers or overlaps with:

A. Legal separation

Adultery is a recognized ground for legal separation (which does not dissolve the marriage but allows separation and property consequences).

B. Annulment/nullity

While adultery itself is not a direct ground for annulment in the same way, it can interact with evidence relevant to marital breakdown or other grounds (case-specific).

C. Civil damages

Even without a criminal conviction, certain civil actions for damages may be explored depending on facts and legal theories (including rights-based or family-relations provisions), but outcomes vary and courts evaluate causation, proof, and applicable law.

D. Child-related implications

Legitimacy rules, support obligations, and parental authority issues may arise.
A criminal adultery case is not automatically a paternity case; separate proceedings may be needed for paternity/support disputes.

14) Risks and liabilities in “evidence gathering”

People commonly make mistakes that create new criminal exposure:

Unlawful interception of communications, hacking accounts, installing spyware, or secretly recording in prohibited contexts can create criminal liability and may wreck admissibility.
Defamation/libel risks from posting accusations publicly.
Harassment or threats can generate separate cases.

In practice, the safest evidentiary route is documentation that is publicly observable, voluntarily provided, or obtained through lawful channels, and then properly authenticated.

15) Practical distinctions: “Adultery vs. VAWC vs. psychological violence”

Adultery is a specific crime with specific elements. Separately, infidelity can be part of the factual matrix in cases under VAWC (RA 9262) when it amounts to psychological violence (e.g., emotional anguish), but that is a different legal theory with different elements, parties, and evidentiary burdens. An adultery case is not interchangeable with a VAWC case.

16) Key takeaways

Adultery requires proof of sexual intercourse and a valid existing marriage of the woman at the time.
The paramour’s knowledge of the woman’s marriage is essential to convict him.
Most cases rise or fall on evidence quality and whether circumstantial evidence excludes reasonable doubt.
The offended spouse’s complaint and issues of pardon/condonation can be decisive.
Criminal prosecution often runs parallel with legal separation, property disputes, support issues, and other family-law consequences.