Do actions have consequences? This is the question House answers through the quote. A husband and a wife, the wife suffering from a sickness which has a few possible causes and the medicine for each one can cure or kill. The decision the husband has to make is whether he trusts his wife so much so as to absolutely deny the possibility that she might have cheated on him. If he trusts her, she might die. If he does not, she might live. What a position to put a person in.
Houseism from the episode – Fidelity (Season 1, Episode 7).