Proving the existence of a common law marriage could be important in several different situations. These include inheriting property, claiming insurance or other benefits, or getting a divorce. Couples ending a common law marriage must go through legal divorce proceedings, just like any other married couple. However, unlike a partner in a certified marriage, a partner who is attempting to obtain either property rights or a right to financial support on the basis of a common law marriage will first have to demonstrate that the marriage was valid. (This will not apply to a claim for child support—states have laws protecting a child's right to support regardless of the legality of the parents' marriage.)
If one partner denies that a common law marriage existed, the other will need clear evidence that both partners intended to be married. In some cases, the length of the marriage will be very important—and may also be the most difficult element to prove, because the relationship may have existed for a period of time without meeting the definition of common law marriage, and then moved into common law marriage territory at some point. Different states require different types of proof.
The critical requirement for a common-law marriage is that both partners agree to the marriage. The best evidence, therefore, would be a written agreement signed by both parties that specifies their intent and includes the date that the marriage began. A written agreement is even more compelling if it has been witnessed by someone other than the couple.
If both partners haven't signed an agreement during the relationship, another strong form of proof would be an affidavit stating an intent to be married that is signed by the person who is now attempting to deny the marriage. This type of affidavit might exist if a person has claimed a common law spouse for a prior legal purpose, such as obtaining insurance benefits. Such an affidavit would generally be notarized, would state the date the marriage began, and might also be witnessed by other parties. An affidavit that was signed during the relationship by the partner now claiming that the marriage is valid would be less conclusive but still helpful, particularly if it shows that the other person accepted benefits from having lawful spouse status.
Even if an agreement or signed affidavit exists, some courts will still require the party claiming the marriage to submit additional evidence of its validity. This requirement may be satisfied by a current affidavit alleging the date that the couple agreed to be married; the state the couple lived in at the time; the addresses of the couple during the marriage; the existence and dates of any previous marriages as well as a description of how any such marriages ended; and a description of any public representations of marriage, including, if possible, names of witnesses to these representations.
The court may also require supporting documents, such as joint tax returns; records of joint bank or credit accounts; deeds or purchase agreements showing joint ownership of property; a will referring to the partner as husband or wife; or any other documents indicating that the couple used the same last name or referred to one another as husband and wife. Other helpful evidence might include testimony or signed statements of witnesses indicating that the parties referred to one another as husband and wife or held themselves out in other ways as a married couple. The exact type of evidence a court will require and accept depends upon the laws in the particular state and the rules of the court receiving the evidence.
If a common law couple separates, or if one partner dies, there may be a time limit on a party's ability to claim rights based on the marriage. For example, in Utah, a party must petition the court for recognition of a common law marriage either during the relationship or within a year following the end of the relationship. Either partner or a third party (such as the next of kin of a partner who has died) may file the petition. In Texas, if no one brings a court action claiming that a common law marriage existed within two years after the parties have stopped living together, a court will presume that there was no marriage, and a party claiming that there was would have to present much more conclusive proof. Even in states that do not specify a time limit, the sooner an action is brought, the easier it will be to prove the existence of the marriage.