The Texas Family Code authorizes a "marital property agreement" between spouses. Pursuant to Chapter 4 of the Texas Family Code, parties must enter into a written agreement to change the nature of their property.Prenuptial and postnuptial agreements can be valuable tools for many couples. Call a Frisco marital agreement lawyer at 972-294-6533. A partition and exchange agreement is a legal contract between divorcing couples that outlines the terms of their property division and distribution. Addressed in a partition and exchange agreement. Note: The same distinction can be made between actual medical expenses and future medical expenses. Discover everything you need to know about Texas separate property agreement forms in this engaging and comprehensive blog.