You already know that you were arrested because of a domestic violence harassment matter that supposedly happened a couple of days ago. So you do know why you were arrested.
Police have no discretion when it comes to domestic violence matters any more. If they have a complaint they make an arrest. Does that mean that a dishonest domestic partner can abuse that process just to get someone arrested and out of the house? Yes, unfortunately, it does. But more often than not, the cases are legitimate and in this way complainants are best protected.
If there is no merit to the case against you, you'll get the opportunity to fight the case in court, and over the time that the case is being fought, your lawyer and you will get to see the discovery with regard to the case so that you will know more about the specifics of the charge. If the complainant and/or witnesses are lying, you'll have the opportunity to confront them at hearings and trial and have your lawyer cross-examine them to show the trier of fact -- judge or jury -- that this charge is a mistake and you are not guilty of anything.
If, on the other hand, when you see the discovery and learn more about the charges, you think the state may be able to prove that a domestic incident did occur, your lawyer can negotiate a disposition with the prosecutor for the best outcome possible under the facts and circumstances alleged against you. When it's over, your bond will be returned, so long as you don't warrant on the case.