Nothing happens next. The DA could file charges in the future but unlikely unless there is a re-occurance of the behavior that lead to the last police complaint.
The above is general legal and business analysis. It is not "legal advise" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
Your attorney is the best source for an intelligent answer to this question. Given the politics surrounding and connected wth domestic violence cases, your attorney was superb. You should also ask or at least give some thought to what will prevent this occurrence in the future.
The above is not intended as legal advice. The response does not constitute the creation of an attorney client relationship as this forum does not provide for a confidential communication.
If you want to be extra cautious, make sure you have something in writing from either your attorney or the DA's office indicating that your case was rejected. If you were given an initial appearance date for arraignment before the case was rejected and you do not have any documentation of the reject, then go to the court clerk's window on the day your case was set for arraignment and they will give you a slip of paper documenting that you appeared and that the case was not filed. T
On a misdemeanor DV case, the DA has up to one year to file the case against you even if they originally chose to reject it. On a felony DV case, the DA generally has up to 3 years to file the case. However, prosecutors usually do not file after they have chosen to reject a case unless there are additional incidents of domestic violence.
This answer is based on California law and procedure and does not create and attorney-client relationship.