Dr. Gerhard Witte, 70, made a brief court appearance Thursday, where he waived a preliminary hearing, the Milwaukee Journal-Sentinel reported.
Elisabeth Witte, who sang with the Minneapolis Symphony Orchestra, was killed during Memorial Day weekend in a parking garage. Police said her ex-husband admitted cutting her throat.
Witte is to be arraigned July 7. Lawyer Gerald Boyle said he will enter the plea then.
Boyle represented one of Milwaukee's most notorious killers, Jeffrey Dahmer. In that case, Dahmer admitted killing 15 people and a jury then determined he did not suffer from mental illness severe enough to remove his responsibility for the crimes.