Broadway star Peters married Wittenberg, an investment advisor, on July 20, 1996 at the home of friend Mary Tyler Moore. She told the Philadelphia City Paper in 2000 that she met her future husband in front of her Manhattan apartment building one night, as she was waiting for a date that was late. "Michael was on his way to a charity event and was in a tuxedo," she remembered. "So he walked up to me, a stranger, and said: 'Are you ready to go?' How's that for a sense of confidence and a sense of humor?"
Both Wittenberg and Peters were involved in the animal rescue charity Broadway Barks. They couple did not have any children.