You really need to read the instructions in full on the USCIS page to give you context. Underneath the part that you had quoted, there were also info such as the following which would apply to you more appropriately:
How to Get a Waiver of the Requirement to File a Joint Petition
If you are unable to apply with your spouse to remove the conditions on your residence, you may request a waiver of the joint filing requirement. You may request consideration of more than one waiver provision at a time.
You may request a waiver of the joint petitioning requirements if:
Your deportation or removal would result in extreme hardship
You entered into your marriage in good faith, and not to evade immigration laws, but the marriage ended by annulment or divorce, and you were not at fault in failing to file a timely petition
You entered into your marriage in good faith, and not to evade immigration laws, but during the marriage you or your child were battered by, or subjected to extreme cruelty committed by your U.S. citizen or permanent resident spouse, and you were not at fault in failing to file a joint petition
Note: Refer to Form I-751 for more specific information on waivers
If You Are In Divorce Proceedings But Are Not Yet Divorced
If you are still married, but legally separated and/or in pending divorce or annulment proceedings, and:
You filed a waiver request. We will issue a request for evidence (RFE) specifically asking for a copy of the final divorce decree or annulment (if applicable).
You filed a Form I-751 petition jointly. We will issue a request for evidence (RFE) specifically asking for a copy of the final divorce decree or annulment and a statement that you would like to have your joint filing petition treated as a waiver.
Upon receipt of the final divorce decree or annulment within the specified time period, we will amend the petition, to indicate that eligibility has been established for a waiver of the joint filing requirement based on the termination of the marriage.
