If your girlfriend had you arrested, getting a factual innocence order to clear your arrest record will depend on the evidence you present and any contradictory evidence that the prosecutor presents in response to your petition.
In a criminal case, the state has the burden to prove that you did something in violation of the law. The reverse is true when you petition for factual innocence. In this case, as the petitioner, or movant, for a factual innocence order, you have the burden to show that no reasonable person would think you were guilty of domestic violence. This standard is meant to prevent orders of factual innocence in cases dismissed because of difficulty proving guilt, because a witness was threatened away, or in the case that someone was acquitted at trial, but is likely guilty. As such, the circumstances of your case must show that you were actually innocent. It's not enough for you to show that your girlfriend now remembers things differently or has somewhat changed her story. If she is going to testify, she should be able to say very clearly that you did not do what she previously accused you of doing.
After you present your evidence for the factual innocence order, the prosecutor for the state will be given the chance to present evidence opposing your motion for factual innocence. They can present the testimony of officers that arrested you. The officers may, for example, testify that your girlfriend seemed scared of you or that she had said you assaulted her. They can also admit photographs taken upon your arrest, such as images of bruises to her face or other injuries that prove something did in fact happen.
Whether your petition for factual innocence is granted or denied is up to the judge. This means the judge is free to disbelieve your girlfriend’s current testimony. The judge may feel that your girlfriend changed her story in an attempt to help you clean up your arrest record. The judge can also choose to accept the prosecutor’s information and determine that a reasonable person would think you were guilty and deserved to be arrested.
A factual innocence order is reserved more for those who are falsely accused. If your girlfriend did not falsely accuse you, but rather has merely had a change of heart and wants to help you clean up your record, other avenues, like a petition to expunge, are probably better suited for your circumstances.
Before you file a petition for factual innocence, consult with a criminal defense lawyer who can walk you through the intent and procedural requirements for factual innocence orders in your state. They can also review the advantages and disadvantages of other options to help put you on the right path to a clean arrest record.