Upon any such Petition presented by a husband, the Petitioner shall make the alleged adulterer a co-respondent 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 a prostitute, and that 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.