What is passive aggressive?
A passive aggressive response is a communicative response which can obstruct an interpersonal relationship. It is often sarcastic and inward feeling leading to the receiver trying to reexplain their thoughts or becoming aggressive, passive or assertive. Often a person can become passive aggressive in their personality trait. It should be noted however that all people can reply in a passive aggressive nature even if it is not their nature.
My husband is having an affair but he looks me in the eyes and tells me he's not is this passive aggressive behavior?
Passive aggressive behavior involves acting in ways that are not directly aggressive, but which express aggressive attitudes. For example, the pot that my wife left on the stove is boiling over, but I let it happen "because she's the one cooking." There's a lot more there than appears on the surface.