There is a procedure to get it changed by filing a case in Court and ask the Court to declare that you are named XYZ and then on the basis of such order, you may get it corrected everywhere
Either you can ask the court to refer you to mediation in the ongoing proceedings and negotiate mutual divorce. In case that does not work out. Withdraw it and file a fresh divorce petition on grounds of adultery. File whatever proofs you have. Make the paramour a party to the divorce.