Jocasta was willing to live in an incestuous relationship with her son as long as the general public didn't find out. It is debatable as to why she would marry someone half her age when she is aware of the prophecy. I suppose that it is possible that, at one time, she believed her son to be dead; possibly at the time of their marriage. It is clear, though, that she became aware of the terrible situation prior to the events of the play. I do believe, however, that Oedipus had no idea that he was laying down with his biological mother.

On the other hand, Jocasta had no such logical excuse. As stated earlier, the possibility certainly existed that, at the time of their marriage, she was oblivious to the true identity of Oedipus. It shouldn't have taken her long, however, to see the scarring and swelling...