The first three acts of The Winter’s Tale are a study of jealousy and its destructive effects. In the play, Leontes’s sudden and unfounded fear that his pregnant wife is sleeping with his best friend eats away at him like a disease. Leontes’s wild jealousy is often compared to that of Othello. Both men unfairly suspect their wives of infidelity and their violent responses destroy their families and upset the political balance. The differences, however, are significant. Unlike Othello, Leontes convinces himself of his wife’s “affair” all by himself – there’s no Iago figure whispering in his ear and goading him along. (If anything, Leontes is his own Iago.) More importantly, Leontes’s abuse of his family is not entirely permanent, unlike Othello’s. After repenting and suffering for sixteen long years, Leontes is reunited with his wife and long-lost daughter, which puts a redemptive spin on The Winter’s Tale, whereas Othello is just plain tragic.
Throughout the play, Shakespeare portrays Leontes’s jealousy as an infectious “disease” in order to highlight the destructive nature of jealousy.
Leontes sudden onset of jealousy is the result of the king’s belief that most women are promiscuous liars and that a man can never really know if he’s the biological father of his children (there being no such thing as DNA testing in the play and all).