Berlitz Breakup

I've been brushing up a bit on my German.

The book German Step-by-Step professes to offer "a vocabulary of 2,600 words chosen especially for their frequency of use." It has a relentlessly chipper tone:

With GERMAN STEP-BY-STEP [sic], accent and pronunciation problems are solved forever. There will be no need to fear appearing gauche before a waiter or salesperson, no terror at buying a train ticket or sending back a steak cooked rare instead of medium. You will discover the music and rhythym of language as spoken by those born into the culture and tradition of a nation.

So I was somewhat shocked by this example conversation in the section on when to use the familiar "du" form for "you". It goes south fast:

Verliebte gebrauchen auch die Du-Form.
Lovers also use the "you" (familiar) form.

SIE:
Liebst du mich?
Do you love me?

ER:
Ja, mein Schatz.
Yes, my treasure.

Ich liebe dich sehr.
I love you very much.

SIE:
Für immer?
Forever?

ER:
Wer weiß? Wer kann das sagen?
Who knows? Who can say that?

SIE:
Warum sagst du — „Wer weiß?"
Why do you say — "Who knows?"

Du bist ekelhaft!
You are horrible!

Ich hasse dich!
I hate you!

Next time they talk, they may have to switch from "du" back to "Sie".