Arthur Miller's The Crucible is not a particularly ironic work; however, there is some irony in how John Proctor characterizes his wife. Proctor has committed adultery with Abigail Williams, a serving girl, in his own house. Elizabeth suspected the relationship and called her husband on it. He confessed to the sin/crime and Abigail was ousted from their home. In the intervening months, the Proctors' relationship has been awkward and stilted. He feels guilty and is trying to regain his wife's trust; she is trying to trust him again and deal with the inevitable issues of inadequacy.
When they share a scene at mealtime, Elizabeth is trying to please John and not totally succeeding (the food isn't seasoned to his taste and she forgot his beverage) and he is trying to please her (offering to get a dairy cow) but failing because he did not tell the entire truth regarding his recent chance encounter with Abigail. When Elizabeth calls John to do what's right and tell the court the girls are lying, he explodes:
You will not judge me more, Elizabeth.... Let you look to your own improvement before you go to judge your husband any more.... Learn charity, woman. I have gone tiptoe in this house all seven month since she is gone. I have not moved from here to there without I think to please you, and still an everlasting funeral marches round your heart.... Let you look sometimes for the goodness in me, and judge me not.
Here it's clear that John sees Elizabeth as his judge, living only to condemn him. Her reply is quiet and believable:
I do not judge you. The magistrate sits in your heart that judges you. I never thought you but a good man, John...only somewhat bewildered.
Proctor has characterized his wife as a judgmental and condemning presence; the irony is that Elizabeth is not the one who's making John feel guilty. It's his own conscience which keeps him on edge and guilt-ridden. We believe Elizabeth when she says she thinks he's a good man; and she confirms it later when she apologizes for being a cold wife whose low self-image probably prompted his lechery. No, it's not Elizabeth who is Proctor's judge. It's the guilty conscience of a God-fearing man, not his judgmental wife, which is making him so miserable.