Incorrect that is not the only requirement...
Kinda of misleading without any references there is more to Common - Law as per CIC links here...
Information on Conditional Permanent Residence
As of October 25, 2012, CIC introduced amendments to the Immigration and Refugee Protection Regulations. The amendments specify that spouses, common-law or conjugal partners who are in a relationship with their sponsor for two years or less and have no children in common with their sponsor at the time of the sponsorship application are subject to a period of conditional permanent residence. The condition requires the sponsored spouse or partner to cohabit in a conjugal relationship with their sponsor for a period of two years after the day on which they became a permanent resident. The conditional measure only applies to permanent residents whose applications are received on October 25, 2012, or after the day that the amendments come into force.
Read the CIC Guide...
http://www.cic.gc.ca/english/information/applications/guides/5289ETOC.asp