Your poems always make me psychoanalyze the pov character, to figure out what's going on in his/her head to phrase things the exact way that's expressed to the reader (which is one reason I enjoy reading them, heh).
The first time I read through this one, my initial impression was, "This is why stay-at-home-mums need to volunteer or find a creative outlet to retain a sense of person beyond the role of mother." What Molly seems to miss is the demands and disappointments, not the laughter and bustle. Then I started thinking maybe it's her way to use "busywork" like ironing and cookery to keep from thinking about things she has no control of.
Very interesting that she considers terror "base." That strikes me as a word with layers of meaning, although it might just be the obvious one. :D
"A chasm in bed" makes me sad for both Arthur and Molly...and makes me want him to encourage her to get counseling and a job volunteering at an orphanage or a wizards' home where her managing ways will be utilized and appreciated . . . and then come home and bridge that chasm, so to speak.
There's a rhyme with "low" and "slow" that doesn't quite fit your scheme. If you'd put What will I do while the hours drag by? or something the pattern wouldn't be off.
People who never heard of "pet rocks" wouldn't chuckle over "A pet. A Rock" read one after the other, but I couldn't help it.
I liked the ending, it made me imagine Molly being able to kill Bellatrix because she's worked herself into the state where she'd cast an Unforgiveable and mean it!
Dark, but very fitting to Molly's character. I love it!