No it isn't. Contract's are agreements between consenting parties. Criminal law is based on the police power of the state. Marriage exists independent of the power of the state and predates the power of the state. It is part of the English common law framework that was adopted wholesale by the original colonies and forms the foundation of the principles enshrined in the constitution. In fact, some were married outside of any state in the US? Are the not lawfully married?
Ask someone who had four wives in a polygamist country, then came with those wives to America.
Can someone tell me how to report abuse?