The Indian Divorce Act, 1869
11. Adultery to be co-respondent. –
union any such petition presented by a husband, the petitioner shall make the alleged adulterer a correspondent to the said petition, unless he is excused from so doing on one of the following grounds, to be allowed by the Court:-
(1) That the respondent is leading the life of prostitute, and the petitioner knows of no person with whom the adultery has been committed;
(2) That the name of the alleged adulterer is unknown to the petitioner, although he has made due efforts to discover it;
(3) That the alleged adulterer is dead.