Is what I communicate to my attorney confidential?
With very limited exceptions, yes. An attorney has a legal duty to maintain inviolate the confidentiality of all confidential information relating to the representation of a client. The exceptions to this rule are: (i) to prevent a criminal act that the attorney reasonably believes is likely to result in death or, or substantial bodily harm, to another; and (ii) the client gives his or her consent to divulge the information. Otherwise, confidential information you tell your attorney cannot be divulged.
As the client, you are the holder of the attorney-client privilege, and therefore you are the only person who can waive that privilege.