Filing a joint tax return is one indicator of intending to enter into a common law marriage. Others are being competent, living together as husband and wife and holding yourself out to others as married.
You have not provided adequate information, but you have certainly suggested the potential for a common law marriage to have arisen through your actions and intent, i.e., a joint tax return.
You indicate he moved in 'recently' and no longer together, but you also indicate you were together long enough to file not one, but two, years of joint tax returns.
Mr. Pate Is giving you good information. There is a good argument that when you completed your tax return, which is generally signed with an expectation that the government can rely on it, and where you did so as a married couple, I expect that your husband could successfully argue that you are married.