If you separated or divorced in 2022, the Canada Revenue Agency (CRA) will still require your ex-spouse’s/ ex-partner’s information. The info is needed for a number of reasons, like eligibility for certain credits or deductions, handling property you still own together, etc…
If you don’t know what it is, you can enter an estimate to continue your return. Then when your ex-spouse has completed their return, you can go back and put the correct income in before you file.