Assuming you are the victim in the case, the district attorney's office may contact you before the next court date, but they may not. If you are anxious, however, you can certainly contact them.
A pretrial hearing is a court date in which, generally, the district attorney makes an offer to resolve the case. Often times, you will get the offer, and your case will be adjourned to give you time to consider it. But, things may work differently in Maryland than they do in Wisconsin.
A pretrial diversion is a deferred prosecution agreement. In other words, the defendant agrees to certain conditions (i.e., alcohol treatment, anger management. maintain work/school, no new arrests, etc.). Then, if the defendant successfully completes those conditions, the case may be dismissed or reduced.
Whether you deciding not to testify will get the case dismissed depends on the facts. If there is enough evidence to convict your husband without your testimony, the district attorney may still proceed with the case. That being said, in DV cases, often times the victim's tesitmony is all the prosecution has.
I would be careful, though. If the district attorney's office subpoeanas you to testify and you refuse, you may be held in contempt of court. Contempt of court can mean fines/jailtime depending on the circumstances and the laws in Maryland.
You may want to consult with an attorney in your area who is experienced in these matters.