TV
Oh, my god. I married the Grinch. I'm Mrs. Grinch!
— Kitty Forman · That '70s Show

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
A comic moment of horrified realisation. The speaker has suddenly decided their spouse is a grump on the scale of a famous holiday curmudgeon, and that this makes them the grump's wife. The exaggeration and the punny 'Mrs.' title carry the humour.
Context reviewed