I. Introduction

Romantic or sexual relationships with a married man are not just a “private moral issue” in Philippine law. They can have criminal, civil, family law, and even administrative consequences—for the married man, his lawful spouse, and, in some cases, the third party (the “other woman” or paramour).

This article explains, in Philippine legal context:

When a relationship with a married man is punishable as a crime
When the “other woman” may incur criminal or civil liability
Effects on marriage, property, and children
Possible administrative and professional sanctions

This is general legal information, not a substitute for personal legal advice.

II. Criminal Law: When the Relationship Becomes a Crime

1. Adultery vs. Concubinage – Which Applies?

The Revised Penal Code (RPC) distinguishes:

Adultery (Art. 333) – committed by a married woman who has sexual intercourse with a man not her husband; the man knowing she is married is also liable.
Concubinage (Art. 334) – committed by a married man who, under any of these modes:
1. Keeps a mistress in the conjugal dwelling; or
2. Has sexual intercourse with the mistress under scandalous circumstances; or
3. Cohabits with her in any other place.

In adultery, the center of gravity is the married woman. In concubinage, it is the married man.

A typical “relationship with a married man” where the woman is single is legally analyzed as possible concubinage, not adultery.

Is the “other woman” criminally liable in concubinage?

Yes, potentially. Under the RPC, the “concubine” (the mistress) also incurs criminal liability, although her penalty is usually destierro (banishment from a certain place), while the husband faces imprisonment (prisión correccional).

But liability exists only if the acts fall under one of the three modes of concubinage:

Kept in the conjugal home
Sexual relations under scandalous circumstances (public knowledge, offensive to public morals)
Cohabiting in another place (living together as if husband and wife)

If the relationship is secret, infrequent, discreet, and does not involve living together or scandalous public behavior, it may be difficult to prosecute as concubinage, even if morally wrong.

2. Who Can File the Criminal Case and How?

For both adultery and concubinage:

Only the offended spouse (the lawful wife) can file the criminal complaint.
The prosecutor cannot file these cases on his/her own (they are not “public crimes” prosecuted ex officio).
The complaint must include both parties:
- In adultery: the married woman and her lover
- In concubinage: the married man and his concubine

If the offended spouse pardons the offender(s), either before the filing of the complaint or after, subject to certain rules, that pardon can bar or extinguish the criminal action.

3. Elements the Wife Must Prove (Concubinage)

In a relationship with a married man, for the wife to successfully prosecute concubinage, she must show:

The man is legally married to her (marriage certificate, etc.); and
He keeps a mistress in the conjugal dwelling; or
He had sexual intercourse with a woman under scandalous circumstances; or
He cohabits with her in any other place.

Evidence can include:

Photos, videos, or messages
Lease contracts or bills showing they live together
Testimony of neighbors/relatives
Social media posts indicating public cohabitation

The mistress can be a co-accused in the case and can be convicted if evidence shows she knowingly participated in the relationship under any of the three concubinage modes.

III. Bigamy and Illegal Marriage

If the married man enters into another marriage with the third party while the first marriage is still valid and undissolved:

He may be liable for bigamy (Art. 349, RPC).
The new “wife” (the former girlfriend/other woman) may also be criminally liable if she knew of the first marriage or actively conspired.

Key elements of bigamy:

A prior valid marriage exists;
The first marriage has not been lawfully dissolved (no annulment, no judicial declaration of nullity, no death);
A second or subsequent marriage is contracted; and
The second marriage would have been valid were it not for the subsistence of the first.

Even if the second marriage is later declared void, the crime of bigamy may still stand if the elements existed at the time of contracting the second marriage.

IV. Civil Liability: Damages Against the “Other Woman” and the Husband

1. Civil Code: Abuse of Rights and Acts Contrary to Morals

The Civil Code provides that:

Every person must, in the exercise of his rights and in the performance of his duties, act with justice, give everyone his due, and observe honesty and good faith (Art. 19).
A person who willfully causes damage to another in a manner contrary to law or good customs is liable (Arts. 20 and 21).

Philippine jurisprudence has recognized the right of the offended spouse (usually the wife) to file a civil action for damages against:

Her philandering husband; and
The paramour, if the latter’s conduct involved bad faith, malice, or acts clearly contrary to morals and good customs.

Damages may include:

Moral damages – for mental anguish, wounded feelings, social humiliation
Exemplary damages – to serve as a deterrent example
Attorney’s fees and costs

The “other woman” may be ordered to pay damages jointly or solidarily with the married man if the court finds that her acts contributed to the wife’s suffering.

2. Property Transfers and Gifts to the Mistress

The Civil Code also restricts donations between persons in illicit relationships:

Donations between persons guilty of adultery or concubinage can be void as against the law and good customs.
The lawful spouse or the conjugal/absolute community of property may sue to recover property transferred to the concubine.

In practical terms: if a married man gives real estate, vehicles, or significant money to his mistress, those transfers can be challenged in court by his wife or his legitimate heirs.

V. Family Law Consequences

1. Duties of Spouses and Marital Infidelity

Under the Family Code, spouses are obliged to:

Live together
Observe mutual love, respect, and fidelity
Render mutual help and support

A relationship with another woman is a violation of the duty of fidelity.

2. Legal Separation

Marital infidelity is a recognized ground for legal separation. The offended spouse (wife) may file for legal separation if the husband:

Commits sexual infidelity; or
Engages in an extramarital affair that causes grave offense or serious marital breakdown.

Effects of legal separation include:

Separation of property between spouses
Loss of the erring spouse’s right to inherit from the innocent spouse (in some instances)
Custody and support orders for common children
The spouses remain married (no remarriage allowed), but they live apart and manage their own property.

The “other woman” is not a party to the marriage case, but she may be named in pleadings and could be called as a witness. Evidence of her relationship with the husband is central to the case.

3. Nullity or Annulment of Marriage

An extramarital relationship by itself is generally not a ground for annulment or declaration of nullity of marriage.

However:

Repeated and long-standing infidelity may be used as evidence of psychological incapacity in petitions for declaration of nullity under Article 36 of the Family Code, depending on the facts and expert testimony.

Again, the focus is on the psychological condition of the spouse, not on the mistress directly, but the relationship is relevant evidence.

4. Children Born from the Relationship

If the unmarried woman has a child with the married man:

The child is considered illegitimate, because the parents were not validly married to each other.
The child may:
- Use the mother’s surname by default;
- Use the father’s surname under certain conditions (acknowledgment and compliance with laws such as RA 9255), but the child remains illegitimate.

Rights of the illegitimate child include:

Support from both parents
Successional rights – the right to inherit from both parents, though with a smaller legitime than legitimate children (as defined by the Civil Code/Family Code).

The lawful wife usually cannot sue the child merely for existing, but she can protect her and her legitimate children’s property rights if any illicit transfers or manipulations of property were done.

VI. Violence Against Women and Children (VAWC) and Infidelity

1. RA 9262: Psychological Violence through Infidelity

The Anti-Violence Against Women and Their Children Act of 2004 (RA 9262) punishes physical, sexual, psychological, and economic abuse committed by a:

Husband;
Former husband;
Present or former boyfriend or dating partner; or
Father of the woman’s child,

against a woman or her children.

Marital infidelity (such as maintaining a relationship with a mistress) has been recognized in jurisprudence as a form of psychological violence against the lawful wife when it causes emotional and psychological suffering.

Thus, the married man may be criminally liable under RA 9262 when:

His extramarital relationship causes the wife severe emotional anguish, humiliation, or mental suffering; and
The elements of psychological violence under RA 9262 are proven.

The “other woman” is not directly charged under RA 9262, because the law is directed at the partner/husband, not the third party. However, her participation may be considered in assessing the overall circumstances. In some scenarios she could face civil liability under the Civil Code for her role.

VII. Administrative and Professional Consequences

1. Public Officials and Employees

Public officers and civil servants may face:

Administrative charges (e.g., immorality, disgraceful and immoral conduct) for maintaining extramarital affairs.
Possible penalties include:
- Suspension
- Dismissal
- Forfeiture of benefits
- Disqualification from future government employment

The unmarried woman may also face sanctions if she is:

A public servant; or
A professional governed by a code of ethics (lawyer, teacher, etc.), and the affair is deemed grossly immoral conduct.

2. Lawyers, Teachers, and Other Licensed Professionals

Professional regulations (e.g., for lawyers under the Code of Professional Responsibility and Accountability, or for teachers and other licensed professionals) often prohibit grossly immoral conduct.

A relationship with a married man, especially if:

Publicly scandalous,
Long-term, and
Clearly destructive of the lawful marriage,

can be used as ground for:

Suspension or disbarment (for lawyers), or
Revocation/suspension of licenses or administrative penalties for other professionals.

The paramour herself/himself, if a professional, may be subject to complaint and disciplinary action.

VIII. Immigration and Other Collateral Issues

While Philippine law governs the status and liabilities, an extramarital relationship can have practical consequences beyond:

Difficulty in obtaining certain visas if it complicates family documentation or raises fraud issues
Complications in reporting family composition for government benefits, housing, or scholarships
Strained relations affecting custody or support arrangements

Though not “legal penalties” in the strict sense, these are real-world effects that often arise alongside the core legal issues.

IX. Practical and Procedural Considerations

Criminal liability is not automatic.
- The wife must actively file the complaint for adultery/concubinage or for RA 9262.
- Without her action, there is usually no criminal case.
Proof is crucial.
- For concubinage, the law requires evidence of keeping a mistress, scandalous intercourse, or cohabitation. Mere rumors or occasional meetings may not be enough.
Civil and criminal cases can go together.
- The offended spouse may file both:
  - Criminal cases (e.g., concubinage, RA 9262), and
  - Civil actions for damages and recovery of illicitly transferred property.
Privacy vs. evidence.
- While everyone has a right to privacy, spouses in court disputes often end up presenting private communications, photos, and financial records as evidence.
Prescription (time limits).
- Crimes and civil actions have prescriptive periods. Waiting too long may bar certain remedies.

X. Summary

A romantic or sexual relationship with a married man in the Philippines can create:

Criminal exposure:
- To the married man and, in some cases, to the “other woman” under concubinage or bigamy, and
- VAWC liability (RA 9262) for the husband due to psychological violence through infidelity.
Civil liability:
- The lawful spouse can sue both the husband and the paramour for moral and exemplary damages, and
- Challenge donations and transfers of property made to the mistress.
Family law effects:
- Grounds for legal separation,
- Evidence in nullity cases,
- Complications involving children (their status, support, inheritance).
Administrative and professional consequences:
- Possible dismissal or sanctions for public officers and professionals involved in scandalous extramarital affairs.

Because the legal consequences are highly fact-specific, anyone directly involved—whether the lawful spouse, the married man, or the third party—should seek personalized legal advice from a Philippine lawyer to understand the concrete risks, defenses, and remedies in their particular situation.