If 40 years ago I did a really dumb thing and married someone so they could become a citizen and have not seen them since, what do I do now?

You should contact an attorney and file for divorce.  You certainly don't want to be charged with Bygamy if you do re-marry.  You can file for divorce in the county you live in and send notice of the petition for dissolution by publication. While you remain married, you may expose yourself to many different types of civil liability.  For more information on Divorce, visit my website at: http://davidleelegal.com/ David Lee