01/17/2009 05:12 am ET | Updated May 25, 2011

CHICAGO — A former suburban Chicago police sergeant who is suspected in his wife's disappearance is engaged to be married again even though he is still legally married, his publicist said Wednesday.

Drew Peterson, whose fourth wife, Stacy, disappeared in October 2007, proposed to the woman within the last week, said Glenn Selig. He would only say that the two began dating about four months ago and that the woman is 23 _ the same age Stacy Peterson was when she disappeared.

Peterson, 54, declined to comment on the engagement but expressed disappointment that the media had found out about it.

"You try to keep a personal life," he lamented in a brief telephone interview with The Associated Press, saying that another relationship he had been in since his wife's disappearance ended when the media found about it.

Peterson's attorney, Joel Brodsky, confirmed the engagement but referred questions about details to Selig.

Peterson, a former Bolingbrook police sergeant who claims Stacy Peterson left him for another man, met with an attorney shortly after the one-year anniversary of her disappearance to discuss filing for divorce on grounds of abandonment. But Peterson and Stacy remain legally married. He is divorced from his first two wives.

Selig said he didn't think Peterson and the woman had set a date for the wedding.

Peterson has been named a suspect in the disappearance of his wife. Authorities say they are investigating the case as a possible homicide.

Authorities are also investigating the death of Peterson's third wife, Kathleen Savio, whose body was found in an empty bathtub in her house in 2004. After Stacy Peterson disappeared, investigators reopened the investigation of Savio's death and reclassified her death as a homicide. Peterson has not been named a suspect in her death.