One of the most common misconceptions
regarding a domestic violence charge is that the victim controls whether or not a case will be prosecuted. Many defendants, in fact it appears that most, believe that the victim can simply "drop" the charge.
In New Jersey courts, prosecutors apply an "evidence-based" analysis of the case. That is, can the complaint be successfully prosecuted?-- even if the victim does not desire to move forward. This is not to say, however, that the victim's opinion is not considered.
In a nutshell, the prosecuting attorney looks for several key pieces of evidence: 1.) visible signs of injury; 2.) third party eye-witness testimony; 3.) "excited utterances"; and 4.) admissions by the accused.
Most of these types of evidence are self-explanatory, but an example of an excited utterance would be a wife saying "my husband just punched me in the mouth," made shortly after the event and when she was excited and/or emotional.
So, when the police respond quickly to a domestic violence incident, see and document personal injury, the wife screams "he did it" and he admits it, then it is far from a foregone conclusion that it will be dismissed-- even if the wife implores that the charges be dropped.