1. Legal Foundations

In the Philippines, adultery and concubinage are criminal offenses under the Revised Penal Code (RPC):

Adultery – Article 333
Concubinage – Article 334
Who may file and how – Article 344 (Prosecution of private crimes)

These are “private crimes”, meaning they cannot be prosecuted by the State on its own initiative. Only the offended spouse may validly start the criminal case, and there are strict conditions and technical rules about how to do it.

The discussion below assumes these provisions remain in force and unchanged.

2. Adultery: Definition, Elements, and Penalties

2.1. What is adultery?

Adultery is committed by a married woman who engages in sexual intercourse with a man who is not her husband, and by the man who knows that the woman is married.

Elements of adultery:

The woman is married.
She has sexual intercourse with a man not her husband.
The man knows that the woman is married at the time of the act.

Important points:

Every act of sexual intercourse is considered a separate offense of adultery.
It is not required that the woman live with the other man.
A purely emotional affair without sexual relations is not adultery (though it may be a ground for legal separation under family law if proven as “sexual infidelity” or similar misconduct).

2.2. Who are liable?

The married woman.
The paramour (the “other man”), if he had knowledge that she was married.

If the man honestly and reasonably believed the woman was single (e.g., she lied convincingly), that may be a defense for him but not for her.

2.3. Penalty for adultery

Adultery is punished by prisión correccional in its medium and maximum periods (a correctional penalty generally ranging from a bit over 2 years to up to 6 years of imprisonment, in various ranges depending on the court’s decision and mitigating/aggravating circumstances), plus accessory penalties (e.g., disqualification from certain rights during the term of the sentence).

In practice, courts may consider mitigating factors such as voluntary surrender or lack of prior convictions, but the formal penalty remains within the statutory range.

3. Concubinage: Definition, Modes, and Penalties

3.1. What is concubinage?

Concubinage is committed by a married man who engages in serious sexual misconduct with a woman not his wife in specific ways defined by law, and by the woman who knows he is married.

The law does not criminalize all forms of infidelity by a husband. It punishes only the following cases (modes):

A married man commits concubinage if:

He keeps a mistress in the conjugal dwelling; or
He cohabits with her in any other place; or
He has sexual intercourse under scandalous circumstances with a woman not his wife.

3.2. Elements of concubinage

Generally:

The man is legally married.
He has sexual relations with a woman not his wife.
The relationship falls into any one of the three modes above.
The woman knows that the man is married.

Key points:

Casual, secret affairs that do not involve cohabitation and are not “scandalous” (publicly shocking) may not fall under concubinage, even if morally wrong.
“Scandalous” usually means publicly offensive, known in the community, or done in a manner that shocks decency.

3.3. Penalty for concubinage

The husband is punished by prisión correccional in its minimum and medium periods (generally lower range than adultery).
The concubine (the “other woman”) is punished by destierro – a form of banishment prohibiting her from entering certain places (including where the offended wife resides) within a radius fixed by the court.

This difference illustrates the inequality between adultery and concubinage in the RPC:

The wife in adultery faces a harsher penalty than the husband in concubinage.
The paramours (other man vs other woman) also face different penalties.

4. Adultery and Concubinage as Private Crimes

Under the RPC, adultery and concubinage are “private crimes.” This has critical consequences:

Only the offended spouse may file a criminal complaint.
- The State, the parents, children, or anyone else cannot validly initiate the case.
- Even the spouse of the paramour/concubine cannot file the criminal case – only the spouse directly offended by the adultery/concubinage can.
The complaint must implead both offenders:
- In adultery: the wife and the paramour.
- In concubinage: the husband and the concubine.
- If only one is charged without a valid legal excuse (e.g., the other is deceased, cannot be found after diligent efforts, or is beyond jurisdiction), the case may be dismissed.
The complaint must come from the offended spouse personally, or through an authorized representative with clear authority.
Without this valid complaint, the prosecutor and the court have no jurisdiction to proceed.

5. Conditions Before a Case Can Be Filed

Even before thinking about evidence and procedure, several legal preconditions must be satisfied:

5.1. There must be a valid marriage

There has to be an existing marriage recognized by Philippine law at the time of the alleged acts.
Annulled or void marriages raise complex issues. As a general rule, the law presupposes a valid subsisting marriage; if a marriage is judicially declared void from the beginning, criminal liability may be questionable.
A mere de facto separation (living apart, no formal legal separation or annulment) does not erase the marriage and does not prevent adultery or concubinage from being committed.

5.2. The case must be filed within the prescriptive period

Adultery and concubinage prescribe (expire) after a certain time. For these crimes, the prescriptive period is generally 10 years, but for adultery and concubinage the law counts prescription from the date the crime was discovered by the offended spouse, not from the day it was committed.

So:

If the last act occurred years ago but the offended spouse learned about it only recently, the 10-year period is usually counted from discovery, not from commission.
Evidence of when the offended spouse discovered the infidelity can be important if prescription is raised as a defense.

5.3. No valid consent or pardon by the offended spouse

The offended spouse cannot file the case if that spouse:

Consented to the adultery or concubinage; or
Expressly pardoned the offenders before the case is filed.

Consent is usually prior or contemporaneous approval (e.g., tolerating the relationship, allowing the other party to live with the mistress/lover).

Pardon is forgiveness after the fact. It may be:

Express – written or verbal clear forgiveness; or
Implied – for example, voluntarily resuming marital relations with full knowledge of the affair, or otherwise clearly treating the wrongdoing as forgiven.

However:

After a case is already filed and properly started, a later “pardon” or affidavit of desistance (saying “I don’t want to pursue the case anymore”) does not automatically extinguish the criminal liability, though in practice it may influence prosecution or plea-bargaining.
Prosecutors and courts still have a duty to determine whether the crime was committed and whether the elements of valid consent/pardon exist under the law.

5.4. The offended spouse must not be barred by law or principle

There is legal commentary and some jurisprudence that an offended spouse who is equally guilty of similar sexual infidelity may be barred from prosecuting the other spouse (under doctrines like pari delicto and based on Article 344’s spirit). Courts evaluate this on a case-by-case basis.

6. Who Can File and Against Whom?

6.1. Who can file?

Only the offended spouse may file the criminal complaint:

For adultery: the husband of the adulterous wife.
For concubinage: the wife of the concubinary husband.

If the offended spouse is a minor or incapacitated, special rules may allow parents or guardians to act, but always in representation of the offended spouse’s rights.

6.2. Against whom must the case be filed?

Adultery: against both the wife and the paramour (if alive and accessible).
Concubinage: against both the husband and the concubine.

If one of them is dead, missing, or beyond jurisdiction, the complaint should state these facts, and the prosecutor/court will evaluate if proceeding against the surviving or present party is legally permissible.

7. Step-by-Step Overview of Filing a Case

(This is a general outline and not a substitute for personalized legal advice.)

7.1. Evidence-gathering by the offended spouse

Before going to the prosecutor, the offended spouse and counsel will normally gather evidence, such as:

Marriage certificate (proof of marriage).
Birth certificates of children born from the affair, if any (to prove paternity or relationship).
Photos and videos showing intimacy, cohabitation, or scandalous acts.
Hotel receipts or records, travel manifests, tickets, or other documents showing the couple staying together.
Text messages, chats, emails, and social media posts (ideally obtained lawfully, to avoid issues with privacy laws).
Witness testimonies – neighbors, friends, relatives, co-workers, hotel staff, etc.
Admissions by either spouse in messages or recorded conversations (subject to rules on admissibility and anti-wiretapping law).

7.2. Consultation with a lawyer

An attorney will:

Assess whether the elements of adultery or concubinage are properly met.
Ensure compliance with private crime requirements (valid complaint from offended spouse, inclusion of both offenders, etc.).
Draft a Complaint-Affidavit.

7.3. Execution of the Complaint-Affidavit

The offended spouse signs a Complaint-Affidavit under oath, usually before a prosecutor or a notary, containing:

Personal details of the complainant.
Details of the marriage (date, place, copy of marriage certificate).
Names and details of the spouse and paramour/concubine.
Dates, places, and circumstances of the adulterous or concubinage acts.
Statements that:
- The complainant did not consent to or pardon the affair.
- The complaint is filed within the prescriptive period.
A list of evidence and witnesses.

7.4. Filing with the Office of the City/Provincial Prosecutor

Venue is generally where the crime or its essential elements took place (often where the sexual acts or cohabitation happened).
The prosecutor’s office then dockets the case for preliminary investigation (unless it’s an inquest case, which is rare for these offenses).

7.5. Preliminary investigation

Subpoena is issued to the respondents (spouse and paramour/concubine), attaching the complaint and evidence.
Respondents file Counter-Affidavits, possibly including:
- Denial of acts.
- Denial of knowledge of marriage.
- Allegations of consent, pardon, or prescription.
- Arguments that the acts do not fall under adultery/concubinage (e.g., no cohabitation, not scandalous).
There may be Reply and Rejoinder affidavits.
The prosecutor evaluates the evidence to determine probable cause.

7.6. Prosecutor’s resolution and filing of information

If probable cause is found, the prosecutor issues a Resolution recommending the filing of an Information for adultery or concubinage in the appropriate trial court.
The court then issues warrants of arrest or summons, depending on the circumstances and discretion of the judge.

7.7. Trial

Once the case is in court:

The accused are arraigned and enter pleas (guilty/not guilty).
There is pre-trial to define issues and mark evidence.
The prosecution presents evidence and witnesses, subject to cross-examination.
The defense presents its evidence and witnesses.
The court issues a judgment:
- Conviction, with penalties (imprisonment or destierro), plus civil damages if claimed; or
- Acquittal, if reasonable doubt exists or legal requirements are lacking.

8. Evidence: What Courts Look For

Because adultery and concubinage are often hidden, courts can rely on circumstantial evidence, not only direct proof of sexual acts.

Common types of convincing evidence:

Repeated overnight stays together in hotels, resorts, or a shared residence.
Public display of affection combined with other circumstances strongly implying sexual relations.
Birth of children whose circumstances strongly indicate they were conceived during the marriage with another partner.
Documented cohabitation (e.g., they rent a place together, neighbors testify they live as husband and wife).
The accused’s own admissions (written, oral, or in social media).

However:

Evidence obtained in violation of privacy rights or anti-wiretapping laws may be excluded.
Suspicion, jealousy, or a single ambiguous incident is often not enough to convict beyond reasonable doubt.

9. Defenses Commonly Raised

Accused spouses or paramours/concubines may raise:

Lack of marriage – e.g., the marriage is void, or no marriage at all.
Lack of sexual intercourse – e.g., the relationship was only emotional or friendly.
Lack of knowledge of marriage – paramour did not know and had no reason to know the partner was married.
No cohabitation or scandalous circumstances – for concubinage, to show that the acts do not fit the particular modes required by law.
Consent or pardon by the offended spouse – prior or subsequent forgiveness, if proven as required by law, can bar prosecution.
Prescription – the complaint was filed beyond the 10-year prescriptive period (counted from discovery by the offended spouse).
Insufficient evidence / reasonable doubt – the prosecution’s evidence is weak, inconsistent, or purely speculative.

10. Relationship to Family Law Remedies

Adultery or concubinage can interact with civil and family law proceedings, including:

10.1. Legal separation

Sexual infidelity or perversion is a ground for legal separation under the Family Code. While this is a separate civil case, the same facts may be used:

The injured spouse can file for legal separation to:
- Live separately.
- Dissolve the conjugal partnership or absolute community.
- Possibly affect rights to property and custody (subject to the best interests of the child).

10.2. Declaration of nullity or annulment

An affair may serve as evidence of psychological incapacity in some cases, or of other grounds, but adultery/concubinage is not itself a direct ground for nullity.
Still, serious repeated infidelity is often used as supporting proof in nullity cases.

10.3. Custody and support

Infidelity does not automatically remove parental authority, but it may influence:
- Child custody decisions (if the affair exposes children to harmful environments).
- Assessment of the moral fitness of a parent.

10.4. Effects on property rights

In legal separation, the guilty spouse may lose certain rights in the conjugal or community property.
Criminal conviction does not automatically strip property, but combined with family law cases, it can have significant indirect consequences.

11. Civil Liability and Damages

From the same adulterous or concubinary acts, the injured spouse may claim civil damages, including:

Moral damages – for mental anguish, wounded feelings, and humiliation.
Exemplary damages – if the conduct was particularly outrageous.
Actual damages – if the injured spouse can prove specific financial loss related to the affair.

Civil liability can be:

Attached to the criminal case (as part of the prosecution), or
Pursued in a separate civil action (e.g., under provisions of the Civil Code for violations of marital rights, privacy, or human relations).

The paramour/concubine can also be civilly liable if the court finds that he/she actively took part in the wrongful acts and caused damage to the offended spouse.

12. Practical and Ethical Considerations Before Filing

Even though the law allows filing, it is often a strategic and deeply personal decision.

Points to consider:

Impact on children – Criminal proceedings are public to an extent; details of intimate relationships may be disclosed in court.
Time and emotional cost – Cases may take years, involve cross-examination, and reopen emotional wounds.
Goal of the offended spouse – Is the objective punishment, leverage in negotiations, moral vindication, or closure?
Possibility of settlement – Some parties eventually opt for civil or family-law settlements instead of extended criminal litigation.

13. Frequently Asked Questions (FAQ) – In General Terms

1. Can I file a case only against the “other woman” or “other man” without including my spouse? Generally, no. For adultery and concubinage, the complaint must be against both the spouse and the paramour/concubine, unless there is a legally recognized reason why one of them cannot be included (e.g., death, cannot be found, beyond jurisdiction).

2. We are already separated in fact. Does that make adultery or concubinage legal? No. Until there is legal separation, annulment, or declaration of nullity, the marriage legally exists. Infidelity can still be adultery or concubinage if other elements are met.

3. If I forgave my spouse before, can I still file now? If there was a valid pardon or clear consent regarding specific acts, the law may bar prosecution for those acts. However, new acts committed after the pardon may still be prosecutable, subject to evidence and prescription.

4. What if I just want to sue the other woman/man for damages, not imprison them? The offended spouse may explore civil actions for damages under the Civil Code, independently of a criminal case. These are separate proceedings with different standards of proof and remedies.

5. Does a criminal conviction automatically decide my annulment/legal separation case? Not automatically. The standards of proof and legal issues differ between criminal and family law cases. However, criminal findings and evidence may be very influential in civil proceedings.

14. Final Notes

Adultery and concubinage cases are legally technical and personally difficult.
Because they are private crimes with strict procedural conditions (who can file, against whom, time limits, and issues of consent and pardon), any misstep can lead to dismissal of the case.
The best course of action for anyone considering such a complaint is to consult a Philippine lawyer who can review the specific facts, assess the sufficiency of evidence, ensure compliance with all legal requirements, and discuss alternative remedies (civil, criminal, or family-law actions).

This overview is meant to explain the general legal framework in the Philippines regarding filing cases for adultery or concubinage against a spouse and paramour, and not to serve as personalized legal advice for any specific situation.