How we cite our quotes: (Act.Scene.Line)
Quote #7
MRS. PEACHUM. They've put his neck just under where the noose is
And what's he thinking of, the idiot? Floozies. (3.7.75-76)
Mac's weakness for women is stronger than his will to live. Even though he knows that if he sticks around town he'll be captured and hanged, as Mrs. Peachum sings, he's overcome by his desire for ladies of the night and goes for them rather than saving his own skin.
Quote #8
You saw the lovely Cleopatra
You know what she became.
Two emperors slaved to serve her lust.
She whored herself to death and fame
Then rotted down and turned to dust. (3.7.268-272)
This song uses historical figures to provide examples of downfalls, and there's a verse dedicated to precisely our sexy theme: lust. Cleopatra had pretty powerful boyfriends, including not only Julius Caesar but Marc Antony, too. Still, when she was finally defeated (in battle) decided to kill herself. The song blames her lust for her downfall, though it might be harping too much on Cleo.
Quote #9
But one fine day his heart was won.
So now that time is getting late
The world can see what followed on.
His sexual urges brought him to this state—
How fortunate the man with none! (3.7.303-307)
The first line of this verse makes it seem like Mac fell in love: "his heart was won," which led to his ignoring his own safety in order to be with his lover. But skip down a few lines and check out what was really going on: "sexual urges." Sorry, Mac—that's not so romantic and therefore unforgivable, at least in the play.