A poem about a woman who exists outsides the boundaries of "normal" life? Why in the world should that have regularized form or meter? Exactly. That's what we thought, too.
In a lot of ways, this poem's form is just one step away from being regular. Sure, it has a rhyme scheme. It even has regularly repeated phrases – like, say, "I have been her kind." But these repetitions just give the illusion of formal regularity.
…and that's where things get interesting. See, the poem is almost in tetrameter. That's a fancy word for a poetic line that has four regular beats and eight syllables (da DUM, da DUM, da DUM, da DUM). Funny thing is, most of its lines have NINE syllables.
And then there's the fact that there are rhymed lines in each stanza – but there are seven lines. (For those of you who haven't been counting, that's one more line than you usually need to wrap up the rhyme scheme with a neat six or eight lines.) Here's the official rundown: ABABCBC. See, any time you have an odd number of anything, it seems like things are a little off balance. There's one lonely line in each stanza. It makes things seem just a tiny bit off kilter, don't you think?
Remember how we said that this poem is about coloring just outside the lines? (See what we have to say about the "Speaker" or in the "Detailed Summary" for some more thoughts on that.) Sexton makes sure that her money (or, in this case, her form) is where her mouth is. No coloring within the lines for her. No, ma'am. The funny part is that she plays close enough to the lines to make us do a double-take. This poem's got all the eerie overtones of formal regularity…but scratch beneath the surface, and it's a whole new deal.