Yes, you do have to testify. The fact is that a subpoena is a court order requiring your appearance. If you ignore it, you can be held in contempt of court at which point a warrant for your arrest can be can be issued. You can also face fines and/or jail time.Some victims try to avoid giving testimony by attempting to invoke their constitutional right against self-incrimination (i.e. pleading the 5th). However, this right doesn't apply simply because a witness doesn't want to testify; it only applies if their testimony would cause them to incriminate themself in the crime at hand or another crime. Additionally, in domestic violence cases, many spouse's try to invoke "spousal privilege", which is the right of one spouse to not have to give testimony against the other spouse. However, most states have made an exception for victims of DV, so now one spouse can be made to testify against the other.At this point, you can consult directly with a local criminal law attorney in your area. They can best advise you further.