How long do we need to be together? Once signed, the declaration is valid proof of marriage and you are considered married for all legal purposes.Outline your shared life: The affidavit asks about how you handled finances, medical decisions, and other critical aspects of your relationship. Personal affidavits: You can write a personal affidavit stating that you and your partner are married. How to Complete a Common Law Marriage Affidavit Form: The affidavit form is typically available online or from legal professionals. These documents safeguard partners' interests, offering a legal safety net in a relationship without marriage's inherent legal safeguards. Present the marriage application with just your information filled in on the document. They can help you understand the legal requirements, complete the affidavit correctly, and ensure your rights are protected. Agreement to be Married Both partners must agree verbally or through actions to be married. Texas Family Code: Chapter 2, Section 2.006.