In the Philippines, extramarital relationships frequently result in children born outside of marriage. These children, classified as illegitimate under the Family Code, possess the same right to support from both parents as legitimate children. When the father is a married man, the mother—commonly referred to as the husband’s mistress or “kabit”—often initiates legal action to secure support for the child. A demand letter prepared and sent by a lawyer serves as the standard first step. This extrajudicial demand formally notifies the father of his obligation, establishes the starting point for accrual of support, and demonstrates the seriousness of the claim before court proceedings become necessary.

Legal Foundation of Child Support Obligations

The Family Code of the Philippines (Executive Order No. 209, as amended) governs support obligations. Article 194 defines support as everything indispensable for sustenance, dwelling, clothing, medical attendance, education, and transportation, consistent with the family’s financial capacity. Article 195 imposes the obligation on parents to support their children, whether legitimate or illegitimate.

Illegitimate children are recognized under Articles 165 to 172. They include children born to parents who are not married to each other at the time of conception and birth. These children enjoy the right to support upon proof of filiation. Filiation may be established voluntarily (through the father’s acknowledgment in the birth certificate, a public document, or private handwritten instrument) or compulsorily through a judicial action for recognition.

Article 203 is particularly important: the obligation to give support becomes demandable from the time the recipient needs it for maintenance, but payment is due only from the date of judicial or extrajudicial demand. A lawyer-drafted demand letter therefore serves as the extrajudicial demand that triggers the father’s liability for current and future support and preserves the right to claim arrears from the date of the letter.

The amount of support is not fixed by law. Courts determine it based on the child’s proven needs and the father’s financial capacity at the time of the demand or judgment. The existence of a legitimate family does not extinguish the obligation to the illegitimate child; however, the father’s total resources are considered, and courts may apportion support proportionally among all dependents.

When the Mother (Husband’s Mistress) Uses a Demand Letter

The mother of the child born from the affair typically engages a lawyer to send the demand letter directly to the biological father (the husband). This approach applies whether or not the father has acknowledged the child. Common triggers include:

The father refuses or fails to provide regular support after the birth.
The father provides sporadic or insufficient amounts.
The mother needs to document the demand for future court action.
The parties have attempted informal negotiations that failed.

The demand letter is addressed to the husband, not the mistress. The mistress is the client who instructs the lawyer and provides the evidence. In rare situations where the legitimate wife seeks to address diversion of conjugal funds to the mistress that should have gone to legitimate children, a separate demand or accounting action may be explored, but the classic use of a demand letter for child support in this context is the mistress enforcing the illegitimate child’s rights against the father.

Why Engage a Lawyer for the Demand Letter

Sending the letter through a licensed attorney offers multiple advantages:

Professional drafting ensures precise citation of the Family Code provisions, proper calculation of support, and clear language that avoids ambiguity.
Evidentiary value: A lawyer’s letter on official letterhead carries greater weight and is easier to present in court.
Proof of service: Lawyers use registered mail with return receipt, private couriers with acknowledgment, or personal service with an affidavit of service, creating a strong record of receipt.
Strategic tone: The letter balances firmness with openness to amicable settlement, often proposing a specific monthly amount, mode of payment, and retroactive coverage.
Follow-through capability: The same lawyer can file the necessary petition if the demand is ignored.

Self-drafted letters by the mother herself are legally valid as extrajudicial demands but are less persuasive and may contain errors that weaken the position in litigation.

Essential Contents of an Effective Demand Letter

A well-crafted demand letter for child support in this scenario typically includes:

Lawyer’s letterhead and contact details, including PTR, IBP, and roll numbers.
Date and complete address of the recipient (the husband). If the exact address is unknown, the letter may be sent to his last known address, workplace, or through relatives.
Reference to the child: Full name, date and place of birth, and any existing birth certificate details.
Proof of filiation: Reference to attached documents (birth certificate naming the father, baptismal certificate, photographs, chat messages, affidavits of witnesses, or prior acknowledgments). If filiation is disputed, the letter may state that an action for compulsory recognition will accompany the support claim.
Statement of facts: Brief narration of the relationship, birth of the child, and the father’s failure or refusal to provide adequate support.
Legal basis: Citation of relevant Family Code articles (194, 195, 203, and provisions on illegitimate children).
Specific demand:
- Monthly support amount (with brief justification based on child’s age, schooling, medical needs, and father’s known income).
- Retroactive support from the date of demand or from birth, if applicable.
- Proposed payment method (bank deposit, cash, or through the lawyer’s office).
- Deadline for compliance (commonly 10 to 15 days from receipt).
Consequences of non-compliance: Explicit warning that failure to respond or pay will lead to the filing of a petition for support, possibly with an application for support pendente lite, plus claims for attorney’s fees, litigation expenses, and damages.
Invitation to negotiate: Many letters include a paragraph encouraging amicable settlement to avoid court.
Lawyer’s signature and dry seal.

Attachments commonly include copies of the child’s birth certificate, school records, medical bills, and evidence of the father’s income (payslips, property titles, or business documents, if available).

Service and Proof of Receipt

Philippine courts require proof that the demand was properly made. Preferred methods:

Registered mail with return card through the Philippine Postal Corporation.
Private courier services (LBC, DHL, FedEx) with signed acknowledgment.
Personal delivery by the lawyer or a process server, documented by an affidavit.
In urgent cases, service through the husband’s employer or known relatives may be used, supplemented by publication if the father is evading service.

The return receipt or signed acknowledgment becomes crucial evidence when the case reaches the Family Court.

What Happens After the Demand Letter

If the father complies, the parties may execute a notarized agreement on support, which can be submitted to the court for approval as a judicial compromise. Payments should be documented through bank transfers or official receipts.

If the father ignores the letter or offers inadequate response, the next step is filing a petition for support (and recognition, if filiation is contested) before the Regional Trial Court acting as a Family Court in the place where the child resides or where the father resides. The petition may pray for:

Monthly support.
Support pendente lite (provisional support granted early in the case).
Retroactive support from the date of the extrajudicial demand.
Attorney’s fees and costs.

Support cases are summary in nature and generally proceed faster than ordinary civil actions. The court considers the child’s best interest as paramount.

Special Considerations in Cases Involving a Married Father

The father’s marital status does not exempt him from supporting the illegitimate child. However, practical realities arise:

Conjugal or community property may be subject to claims, but the legitimate family’s needs are also protected.
The legitimate wife may separately pursue actions for support of the legitimate children or even file for legal separation or annulment on grounds of sexual infidelity.
Criminal liability (concubinage under the Revised Penal Code) may exist if the husband and mistress cohabit, but this is independent of the civil support obligation.
Republic Act No. 9262 (Anti-Violence Against Women and Their Children Act) primarily protects the legal wife and legitimate children, but the illegitimate child may still benefit from protective orders in appropriate circumstances.

DNA testing may be ordered by the court if filiation is denied. The cost is usually shouldered by the party requesting it, though the court may allocate expenses equitably.

Challenges and Practical Tips

Common challenges include the father’s denial of paternity, concealment of income, or claims of financial inability. The mother should gather strong evidence early: financial records, witness statements, and documentation of the child’s expenses.

Prescription does not run against the right to future support, but claims for arrears are generally enforceable within ten years under the Civil Code. The demand letter preserves and starts the running of the period for retroactive claims.

Mothers are advised to keep all communications civil and to document everything. Emotional language in the demand letter should be avoided; facts and law must predominate.

Judicial Remedies and Enforcement

Once a judgment for support is obtained, enforcement follows the Rules of Court. Writs of execution may be issued against the father’s salary, bank accounts, or properties. Continuous failure to pay can lead to contempt proceedings or even criminal charges for violation of a court order.

In extreme cases of abandonment and non-support, the mother may also explore filing for custody (if not already with her) or applying for protection under child welfare laws.

The demand letter through a lawyer remains the most efficient, cost-effective, and legally sound initial step to enforce a child’s right to support when the father is a married man involved in an extramarital relationship. It respects the extrajudicial demand requirement of the Family Code while positioning the case strongly for judicial intervention if necessary. In a jurisdiction where family relations and the best interest of the child guide all decisions, this formal demand often prompts settlement and ensures the illegitimate child receives the support to which he or she is legally entitled.