In order to establish that you are in a common law relationship – usually for the purposes of meeting the baseline eligibility requirements for being a “spouse” who is entitled to support – you and your partner must have lived together continuously as a couple:
a) for at least three years; OR
b) for any length of time, as long as you are in a “relationship of some permanence” and have a child together.
Interruptions in the period of living together due to relationship discord, or periods where you are not physically together, will not necessarily disqualify you from meeting the threshold. It all depends on the circumstances, including the nature of your relationship and living situation.