How do I prove that I am a spouse, partner or surviving partner?

To prove the status of spouse of a deceased person, the civil marriage register must be presented. On the other hand, to prove the status of permanent partner, the existence of the common-law marriage must have been declared, and if it was not declared during the lifetime of both, you must go, through a lawyer, before a family judge to declare the common-law marriage. 

Note: for more information on how to declare a common-law marriage, please refer to the specific question.