Most Massachusetts prosecutors take domestic violence very seriously and will work hard to prosecute a case where charges have been filed. Your wife will not be able to withdraw her complaint, but she can indicate to the prosecutor that she doesn’t want to pursue the matter and doesn’t plan on cooperating with the prosecution. That will have some impact, but not necessarily conclusive.
If she fails to show up and provide testimony, she can be subpoenaed and compelled to testify – failure to abide by the subpoena is contempt, and lying under testimony is perjury – both are very serious matters.
If your wife’s testimony against you would also incriminate herself, then your wife can plead relief from testifying under the 5th amendment, and if plans to do so she should inform the prosecutor of her intent before the court date. Prosecutors don’t like to walk away from a case while it is being heard in court. If your wife pleads her right against self-incrimination and the prosecutor still wants her testimony – the judge will assign an independent attorney to confirm she has grounds – if she does she’ll be excused.
A prosecutor’s decision to prosecute is also dependant on how much additional evidence he/she has besides your wife’s testimony – for example: photos, police testimony, and other witnesses like neighbors and family members.
This is not legal advice and is not intended to create an attorney-client relationship. You should speak to an attorney for further information.
If your wife filed a false report she will not want to compound her problem with false testimony. The state - specifically the Victim Witness Advocate will try to persuade her to testify against you. One of the problems about domestic violence litigation and prosecution is that it keeps happening and the family eventually becomes a statistic.
A common misconception is that the alleged victim in a criminal case can "drop the charges", like a plaintiff in a civil suit. This is simply not true for criminal cases, as once the prosecution has begun, it is the state and not the alleged victim who decides whether or not to go forward on the charges. The Commonwealth will not dismiss the case unless it has to, even when the alleged victim (your wife) indicates that she will not testify.
Just because the Commonwealth will not dismiss a case prior to trial does not mean, however, that it can actually start a trial against you without your wife's testimony. If you wife is the only witness to the alleged crime, and she asserts her marital privilege, the prosecution will not have any evidence against you on the day of trial, and they will have no choice but to answer not ready for trial, at which point your attorney asks the judge to dismiss the charge. The prosecution will try, via their victim witness advocate, to persuade your wife to testify against you, but it sounds like your wife has both a marital privilege as well as a 5th amendment privilege (because of the false report to the police) to refuse to testify.
As others have advised, once charges are filed, the victim has little say in whether or not the Commonwealth prosecutes the case or not. Since you are married, your wife may claim her Marital Privilige and refuse to testify against you. However, she must be careful and not recant her previous statements or she can compound the issue by having new charges brought against her, such as perjury or filing a false police report. A big issue will be whether there is any independant evidence against you without your wife's testimony. This could be taped 911 calls, turret tapes (communications between cruiser and dispatcher), or other witnesses who saw the event themselves. You should hire the best criminal defense attorney that you can afford who regularly practices in the court in which you are charged. He/she will likely have knowledge of the players (ADAs and judges) and hopefully have prior experience with these people, which is highly beneficial. Since Domestic Violence is such a hot political topic, Assistant District Attorney's (ADAs) are loathe to drop these charges and try to prosecute them aggressively. Hire an attorney that you feel comfortable with and take the advice they provide you.