The question is, whether A and B, were married. The fact that they were usually received and treated by their friends as husband and wife, is relevant. This illustration is mentioned in –

Section 50 - Opinion or relationship, when relevant: When the Court has to form an opinion as to the relationship of one person to another, the opinion, expressed by conduct, as to the existence of such relationship, or any person who, as a member of the family or otherwise, has special means of knowledge on the subject, is relevant fact: Illustrations (a) The question is, whether A and B, were married. The fact that they were usually received and treated by their friends as husband and wife, is relevant.