The answer would be yes, as your marital status was Common-law partners initially. Therefore, when you start filing your return for this year, you're asked for your marital status as of December 31st, 2020, you can enter it as "Separated" and answer "Yes" to the question "Did you separate from your spouse/partner in 2020?".
Further, you'll be asked for your Date and Month of separation including the Marital status prior to the separation. Here, you can enter the details.
Hope it helps.
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