You enter into a certain amount of madness when you marry a person with pets.

Ephron’s line treats marriage as an entry into an already-established ecosystem: when you marry someone with pets, you also marry the routines, messes, expenses, and emotional loyalties that come with them. Calling it “a certain amount of madness” is affectionate rather than condemning—an acknowledgment that domestic life is inherently irrational and negotiated, especially when nonverbal creatures with their own needs and habits are involved. The humor rests on a recognizable truth: pets can complicate intimacy and logistics, but they also reveal character and capacity for care. The quote ultimately frames partnership as accepting (and even embracing) another person’s small, chaotic attachments.