What is the relationship between Jocasta and Oedipus?

Jocasta is both the wife and mother of Oedipus, making this choice accurate within the context of the play. This complex relationship arises from the tragic circumstances of Oedipus's life, where unknowingly he fulfills a prophecy that states he will kill his father and marry his mother. Jocasta was once married to Laius, Oedipus’s biological father, and upon Laius's death, Oedipus, not realizing Jocasta's true identity, marries her. Their relationship is central to the themes of fate and identity in the narrative, highlighting the tragic consequences of the characters' actions and the inescapability of their fates.

The other answers suggest relationships that do not align with the plot of the play, as Jocasta is not Oedipus's sister, cousin, or merely a friend.