Man of the House

I'm not understanding S3, the first 6 lines. Are the dashes related? Do they wrap a semantic package, or does the semi-colon pair up with the first dash in closing that subordinate structure?

And a Q regarding the following passage:

had me mouthing “never agains”

almost as sincerely false

as his broken record of promised abstinence

in appreciating the double-take for 'broken record', I wonder if that passage might be sharpened by omitting the rather obviously oxymoronic 'sincerely false' with something like 'with a sincerity matched (only)/by his broken record...'?