Defended cases are extremely rare as people commonly recognise that there is little point in trying to keep a marriage alive when the other person considers the relationship to have ended. It can also be very costly, so in the majority of cases it is not advisable.
If a defence is filed there has to be a hearing where the judge will decide if there is sufficient evidence for divorce or in the case of a cross petition (where the other spouse has declined the reasons for divorce and put forward their own reasons) whether either or both have adequate grounds for a decree to be granted. Usually a draft petition will be sent to the other party for comment before it is sent to the court, in the hope that an agreed petition can be lodged instead.