Should I file as a single or common law when my common law partner will not give me her social insurance number or income even though we live together and have a child?

[Delphision · Accepted solution]

You can go ahead and file using 000 000 000 for her social insurance number.  Put in a reasonable estimate of her income, and make it sufficiently high enough that you don't get a spousal deduction.  Let your spouse know that you are filing legally and if she does not do the same, her returns are apt to be reassessed at some time.  This will be very costly if she is filing a deduction for eligible dependant that she is not entitled to claim.