Common Law Laws (in the few states that allow them) too rigorous: they support an antiquated CUSTOM of women not using their birth surnames AND using the perjorative terms "husband" and "wife":

• a heterosexual couple lives together in a state that recognizes common law marriages
• for a significant period of time (not defined in any state)
• holding themselves out as a married couple -- typically this means using the same last name, referring to the other as "my husband" or "my wife" and filing a joint tax return, and
• intending to be married.