Sometimes the only reason we know that a divorce took place in our family tree is through a "D" in the marital status column of a census or on a marriage registration where one of the parties is not listed as a widow, widower, spinster or bachelor. Even then, due to the stigma at that time of being divorced, the truth might not have been told.
For many years one of the few ways a divorce in Canada could be granted was through an act of the Canadian Parliament. A searchable index of those divorces listed as Private Members bills between 1841 and 1968 that were granted by the Parliament of Canada can be found on the Library and Archives Canada site on the Acts of Divorce, 1841-1968 page. The results will indicate what book, year and citation to consult in order to find the details of the cause for the divorce along with the date it was granted. The Canada Gazette will usually also have mention of the fact that a petition is being brought forward requesting a divorce.
Start by searching on the surname of the petitioner and then, if not found, search on the surname of the spouse. Remember that when searching your initial search should be broad (surname only) and only if there are too many results returned should you add a forename. The search allows for the wildcard symbol,"*", to be used. So Will* will find William and Williams along with other names that start with Will.
However, the provinces could also grant divorces. The Divorce research aid page on the Library and Archives Canada Genealogy site also provides suggestions as where you can find the records held by the provinces. Also, you may sometimes come across mention of the divorce in the local newspaper.
So if you can't find the divorce in the Acts of Divorce by the Parliament of Canada make sure you check out the provincial resources.