Characters
He can't do without me, you know.
— Mrs. Honeychurch · A Room with a View

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The speaker insists that a certain man cannot manage without them. The words carry a self-important, possessive note, presenting the speaker as indispensable, though 'you know' invites agreement and may suggest they are reassuring themselves as much as informing the listener.
Context reviewed