You need a lawyer badly, and you may have put yourself into a horrible jam.
This case is a high and aggravated misdemeanor, and if you lose after trial you can face up to a year in jail.
If your wife has told the DA that she doesn't want to press charges, and the DA agrees to drop, there will be no trial tomorrow, because the DA will just dismiss the case. On the other hand, it's not your wife's call as to whether this case gets dropped or not. It's the DA's. The DA can subpoena your wife and make her come in and testify or face contempt charges.
If the DA told your wife he's not dropping the case, the DA probably does not need your wife tomorrow. There should be pre-trial hearings, not that you've asked for them, but if not, there would be jury selection. That takes time and she wouldn't be needed for that.
I suggest going in and informing the court that your wife is not interested in prosecuting and that therefore the state isn't really ready for trial. If they say, "Oh, yes we are," ask for a continuance to come back with a lawyer.