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 your ex-spouse’s income, then you can either put an estimate or enter Zero. Either way, do not claim the spousal amount.
For their SIN, you can look at your tax returns from previous years (T1 Form).