Characters
Adopt a less marital tone.
— Marquise De Merteuil · Dangerous Liaisons

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker curtly instructs someone to speak less like a spouse. The command implies the person's manner presumes a familiarity the speaker wants withdrawn, and asks for more distance. Its cool precision turns tone of voice into a matter of control.
Context reviewed