Short answer. Yes, as to your partner's share. Family Code Article 148 provides that if one of the cohabiting parties is validly married to another, that party's share in the co-owned property accrues to the absolute community or conjugal partnership of that valid marriage, not to your partner personally, and not to you.
What the law says
If one of the parties is validly married to another, his or her share in the co-ownership shall accrue to the absolute community or conjugal partnership existing in such valid marriage.
Family Code, Article 148 — Property of Unions Without Marriage (Not Capacitated). Read the full provision →
How property is owned under this kind of cohabitation
Article 148 governs cohabitation between people who are not capacitated to marry each other, which includes a live-in relationship where one partner is already validly married to someone else. Under this rule, only the properties acquired by both of the parties through their actual joint contribution of money, property, or industry shall be owned by them in common in proportion to their respective contributions. Contributions and shares are presumed equal absent proof otherwise. So the starting point is ordinary co-ownership between you and your partner, measured by what each of you actually put in, not automatic community property the way a marriage would create.
Where the married partner's share goes
The article then redirects the married partner's own share away from them personally: if one of the parties is validly married to another, his or her share in the co-ownership shall accrue to the absolute community or conjugal partnership existing in such valid marriage. Practically, this means your partner's portion of the jointly built property does not stay with your partner to dispose of freely; it is treated as belonging to the property regime of their existing, valid marriage. Their legal spouse, through that community or partnership, effectively acquires an interest in it.
What happens to your own share
This redirection applies only to the share of the party who is validly married, based on how the article is written. Your own share in the property, measured by your actual contribution, is not swept into your partner's marriage; it remains yours as a co-owner. The article separately addresses forfeiture of a bad-faith party's share in other circumstances, but the specific rule that answers your question is this one: the married partner's portion goes to their own marital property regime, and their legal spouse's claim reaches the property through that regime rather than reaching your own contribution.
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.
- Bernard B. Benasa vs. Presentacion R. Mahor, G.R. No. 236659, August 31, 2022 — read the decision on LawPhil →
- Guillerma Tumlos vs. Spouses Mario Fernandez and Lourdes Fernandez, G.R. No. 137650, April 12, 2000 — read the decision on LawPhil →
- Sally Go-Bangayan vs. Benjamin Bangayan, Jr, G.R. No. 201061, July 3, 2013 — read the decision on LawPhil →
- Agrifina Dultra Vda. De Cañada vs. Cresencia Baclot, substituted by Sanchito Baclot, et al, G.R. No. 221874, July 7, 2020 — read the decision on LawPhil →