Short answer. Yes. The absolute community is liable for the support of the spouses, their common children, and the legitimate children of either spouse. A child of your spouse's earlier valid marriage is a legitimate child of that spouse, so their support is a community charge.
What the law says
The support of the spouses, their common children, and legitimate children of either spouse; however, the support of illegitimate children shall be governed by the provisions of this Code on Support
Family Code, Article 94 — Charges on the Community Property. Read the full provision →
Stepchildren are covered because of their status, not yours
The clause does not speak of children of the marriage. It speaks of legitimate children of either spouse, which is a wider category on purpose. A child born to your spouse within an earlier valid marriage is that spouse's legitimate child and stays so, whatever later became of that marriage. Nothing in the clause requires that you have adopted the child, or that the child lives in your household. The community's liability follows the child's status in relation to your spouse, not the child's relationship to you.
Illegitimate children are handled elsewhere in the same article
The clause draws the line itself: the support of illegitimate children is instead governed by the provisions of this Code on Support. A later paragraph of the same article then adds that where the debtor-spouse's exclusive property is absent or insufficient, the community advances that support — and what it advances is deducted from the share of the debtor-spouse upon liquidation. So both kinds of children may end up supported from community funds, but only one of them costs your spouse a slice of their own share at the end.
The article says who pays, not how much
It is worth being clear about the limits of this clause. It allocates the obligation to the community; it does not fix the amount. What support consists of, and how much is due in a given case, come from the Family Code's own title on Support, which measures the obligation against the resources of the person giving it and the needs of the person receiving it. So the answer to must the community pay is yes, while how much is a separate question resolved under different provisions.
Practical effect during the marriage
Because it is a listed charge, support for your stepchild is not a discretionary expense your spouse has to justify to you, and it is not booked as a loan against their share. It ranks alongside the support of the spouses themselves and of your common children. If the community property is not enough to cover the article's liabilities generally, the closing paragraph makes both spouses solidarily liable for the unpaid balance out of separate property, and support under this clause is not among the exceptions to that rule.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Philippine National Bank vs. Venancio C. Reyes, Jr, G.R. No. 212483, October 5, 2016 — read the decision on LawPhil →