Yes if your common-law spouse meets the requirements below, you can claim them.
According to Canada Revenue Agency (CRA) your marital status for tax purposes can be:
Married means that you have a spouse. This term only applies to a person you are legally married to.
Living common-law means thatyou are livingin a conjugal relationship with a person who is not your married spouse, and atleast one of the following conditions applies:
This personhas been living with youin a conjugal relationship for at least 12 continuous months
This person is the parent of your child by birth or adoption
This person has custody and control of your child (or had custody and control immediately before the childturned19 yearsof age) and your child is wholly dependent on them for support