From the
OP2 Processing Manual - Section 5.35
What is cohabitation?“Cohabitation” means “living together.” 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. The continuous nature of the cohabitation is a universal understanding
based on case law.
While cohabitation means living together continuously, from time to time, one or the other partner
may have left the home for work or business travel, family obligations, and so on. The separation
must be temporary and short."
The reason they won't specifically define "temporary and short" is because it's left to the discretion of the VO assessing the application. They will factor into their overall assessment whatever "absences" may have occurred, and decide whether they seem reasonable within the context of the partnership.