Here is the relevant page on assessing common law relationships:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/permanent-residence/non-economic-classes/family-class-determining-spouse/assessing-common.html
Maddeningly the main relevant section is very short: "Two people who are cohabiting have combined their affairs and set up their household together in one dwelling. To be considered common-law partners, they must have cohabited for at least one year. This is the standard definition used across the federal government. It means continuous cohabitation for one year, not intermittent cohabitation adding up to one year."
On the other hand, this reference to 'standard definition used across the federal government' provides an opening that since this is used across federal government, there is or should be relevant case law and admin practices and some level of uniformity or consistency in treatment. In other words, if you can find any basis to say that this evaluation (refusal) seems to be obviously inconsistent with levels of evidence and "householdness", you have a better chance of a positive reconsideration. (This is a narrow area where a lawyer may be able to help provide specific language in request for reconsideration and/or appeal, that the level of inconsistency is in spirit entirely at odds with "the standard definition and practice across the federal government.")
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/permanent-residence/non-economic-classes/family-class-determining-spouse/assessing-common.html
Maddeningly the main relevant section is very short: "Two people who are cohabiting have combined their affairs and set up their household together in one dwelling. To be considered common-law partners, they must have cohabited for at least one year. This is the standard definition used across the federal government. It means continuous cohabitation for one year, not intermittent cohabitation adding up to one year."
On the other hand, this reference to 'standard definition used across the federal government' provides an opening that since this is used across federal government, there is or should be relevant case law and admin practices and some level of uniformity or consistency in treatment. In other words, if you can find any basis to say that this evaluation (refusal) seems to be obviously inconsistent with levels of evidence and "householdness", you have a better chance of a positive reconsideration. (This is a narrow area where a lawyer may be able to help provide specific language in request for reconsideration and/or appeal, that the level of inconsistency is in spirit entirely at odds with "the standard definition and practice across the federal government.")