If you don't want to prosecute, you have to let the state know. They are entitled to press charges whether you like it or not, but your input is still important.
Start by contacting the police and telling them that you want to drop the charges. Tell them that you never wanted him to face criminal charges. If they haven't turned the case over to the prosecutor yet, they may let drop this.
If the police can no longer help because they have already involved the DA, you need to go to the prosecutor's office and speak to the one who is assigned to the case against your husband. Tell him/her that you already told the police you are not interested in prosecuting, and tell them why. Let the prosecutor know you want the case against your husband dismissed.
In my experience, the DA is going to be most concerned about your safety. And as a matter of national policy when it comes to domestic cases, the odds are close to 100% that the prosecutor will tell you that it's too late for you to drop and that once a domestic violence matter is filed with the court, it becomes the state's case and not yours any more. The state can choose to go forward with the case whether the original complainant cooperates or not.
He will also tell you that if you refuse to cooperate, he can subpoena you , bring you into court in handcuffs, if necessary, put you on the stand and require you to testify against your husband. These facts are all perfectly true.
Realistically speaking, however, unless there are other witnesses or medical evidence, prosecutors usually can't win their domestic violence case without the cooperation of their key witness -- who is in this case you. So if you stick to your guns and refuse to change your mind, and if you don't make yourself available to the prosecutor, most of them will eventually opt to cut their losses, once they are sure that nobody has forced you to drop the charges, and once they are sure that you are going to be safe.
To expedite the resolution of this case, you need to see to it that your husband is represented by counsel and talk to your husband's lawyer once he has one. You can let him or her know that you have been trying to drop charges but that the prosecutor won't let you and that you don't want to cooperate or go forward with the case. Ask for the lawyer's help with the prosecutor. His lawyer should be willing to talk to the prosecutor for you, as the lawyer and you want the same thing: for your husband's case to be dismissed.
Not always but usually, when the complainant and the defense lawyer join forces to double-team a prosecutor to convince him drop charges, something favorable to the defendant, even if it's not a direct dismissal, can be worked out. In part, this is often because the judge will get impatient and eventually get into the act and tell the prosecutor that he ought to resolve this and stop wasting the court's time with a case that is clearly going nowhere.