5 CFR 1651.5 - Spouse of participant.
(a) For purposes of payment under § 1651.2(a)(2) and establishment of beneficiary participant accounts under § 1651.19, the spouse of the participant is the person to whom the participant was married on the date of death. A person is considered to be married even if the parties are separated, unless a court decree of divorce or annulment has been entered. The laws of the jurisdiction in which the marriage was initially established will be used to determine whether the participant was married on the date of death.
(b) If a person claims to have a marriage at common law with a deceased participant, the TSP will pay benefits to the putative spouse under § 1651.2(a)(2) in accordance with the marital status shown on the most recent Federal income tax return filed by the participant. Alternatively, the putative spouse may submit a court order or administrative adjudication determining that the common law marriage is valid.