David Petraeus, one of America's most decorated generals, is expected to make his public comeback Tuesday night with an apology for the extramarital affair that led to his resignation.

Petraeus is to quaintly refer to the affair as "slipping his moorings" during a speech at the University of Southern California.

Petraeus resigned as CIA director in November after the affair was discovered during an FBI investigation into a potential breach of security that involved email exchanges.