“If someone has a kesubah and kiddushing [sic] and huppah (and arguably merely bi’ah, at least in states that allow common law marriage) – they are married meaning they are required to file joint tax returns, are liable for each other’s debts, and the father has no way out of supporting the family, etc. – and they can be prosecuted for bigamy if they have a ‘get’ without a civil divorce, which means a subsequent marriage will be void under state law.”
Married couples are not required to file joint tax returns. They must state on their tax returns that they are married, but they may file separately or jointly. Depending on the couple’s financial situation, that decision may save them hundreds or, occasionally, thousands of dollars.