my son's exwife has told her attorney, his assistant in writing that I have had several DUI's when I have had none?

In Virginia, there is no difference between slander (oral) and libel (written); they are both treated equally, as “defamation.”  A defamatory statement is a false statement of fact which is “published” and which harms your reputation.  “Published” just means that the speaker made the statement to someone other than you.  The law will assume that your reputation was harmed by a defamatory statement about your criminal history.  This is called “defamation per se” and also applies to statements about your professional abilities.  Truth is an absolute defense to a defamation case.However, Virginia also recognizes a “qualified privilege” in certain situations.  The qualified privilege means that the plaintiff has to show that the speaker knew the statement was false or acted with reckless disregard for its truth.  Virginia also recognizes an absolute judicial privilege, meaning that virtually any statement, even if defamatory, made in the course of a legal proceeding, cannot be the basis for a defamation suit.  The question in your case is whether the judicial privilege applies.  If she made the statements about your criminal history with the intent that they go into a document to be filed in court, the judicial privilege may extend to the communication with her attorney.  It depends on the detailed facts of your case.Loss of a security clearance could potentially be an item of damages in a defamation suit.If you are concerned about your ability to pick up your grandchildren, you should consult with a family law attorney licensed in Virginia.