Unfortunately, you can not claim your common law as a dependant.

As per the Canada Revenue Agency (CRA):

The dependant must be one of the following persons by blood, marriage, common-law partnership or adoption:

• your parent or grandparent
• your child, grandchild, brother, or sister under 18 years of age 
• your child, grandchild, brother, or sister 18 years of age or older with an impairment in physical or mental functions

However, it is possible for you to claim a spouse or common-law partner amount if, at any time in the year, you supported your spouse or common-law partner and their net income from line 23600 of their return (or the amount that it would be if your spouse or common-law partner filed a return) was less than your basic personal amount (plus $2,499 if your spouse or common-law partner was dependent on you because of an impairment in physical or mental functions).

To get more details, please read Line 30300 – Spouse or common-law partner amount.

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