Short answer. Not by simply amending the settlement itself. Family Code Article 76 requires modifications to be made before the wedding, but that rule is expressly made subject to Articles 66, 67, 128, and 135, so a judicial separation of property granted on one of Article 135's recognized causes can still change your property arrangement afterward.
What the law says
In order that any modification in the marriage settlements may be valid, it must be made before the celebration of the marriage, subject to the provisions of Articles 66, 67, 128, 135 and 136.
Family Code, Article 76 — Modifying Marriage Settlements Before the Marriage. Read the full provision →
The general rule: before the wedding, not after
Article 76 states the timing rule plainly: in order that any modification in the marriage settlements may be valid, it must be made before the celebration of the marriage. A marriage settlement is meant to be fixed once the wedding happens, and spouses generally cannot go back afterward and simply amend its terms by agreement the way they negotiated it beforehand. Ordinarily, then, the answer to modifying a settlement after your wedding would be no.
Why judicial separation of property is different
Article 76 does not stop there; it makes the before-the-wedding rule subject to the provisions of Articles 66, 67, 128, 135 and 136, meaning those articles carve out situations where the property arrangement can still change after the marriage. Article 135 lists sufficient causes for judicial separation of property, including that a spouse has abandoned the latter or failed to comply with his or her obligations to the family, and Article 128 separately lets an abandoned or aggrieved spouse petition the court for judicial separation of property on that basis. A court granting separation of property under either of these does not amend your original settlement document, but it does change how your property is managed and owned going forward.
What this means for your situation
If you are pursuing a judicial separation of property on one of the causes Article 135 recognizes, or on the abandonment ground Article 128 describes, you are using the mechanism Article 76 itself acknowledges as an exception to the before-the-wedding rule, rather than trying to directly modify the settlement's terms by mutual agreement after the wedding. The outcome, a changed property regime between you and your spouse, is achieved through the court process these articles set up, not through simply rewriting the settlement document the two of you signed. The petition, the grounds relied on, and the court's own order are what carry legal weight here, rather than any private amendment the two of you might otherwise attempt to draft and sign on your own.
Related provisions
- Family Code, Article 76 — Modifying Marriage Settlements Before the Marriage
- Family Code, Article 128 — Abandonment and Failure of Obligations
- Family Code, Article 135 — Sufficient Causes for Judicial Separation of Property