This is a brilliant poem that certainly stands as an antidote to the saccharine-sweet nature of the original fairy tale. You might like to start by considering how Sexton introduces the rags-to-riches genre by providing us with a series of modern day examples of characters who move from a state of poverty to incredible wealth. After each one, she seems to dismiss them with the repeated phrase, "That story," as though to question the happily-ever-after that they leave their protagonist with. This is something she further develops with her treatment of the Cinderella story. Note her cynicism and scepticism in the final stanza when she talks about the ending of the Prince and Cinderella:
Cinderella and the prince
lived, they say, happily ever after,
like two dolls in a museum case
never bothered by diapers or dust,
never arguing over the timing of an egg,
never telling the same story twice,
neer getting a middle-aged spread,
their darling smiles pasted on for eternity.
Regular Bobbsey Twins.
Their happily-ever-after ending that the poem gives them is deliberately made fun of and ridiculed. Sexton seems to suggest that such an ending is so outside of the sphere of reality, as calling them "Regular Bobbsey Twins" suggests, that it cannot be related to. In addition, from the list of what characterised their future, we could argue that Sexton is actually suggesting happiness lies in growing old with somebody and getting a "middle-aged spread." Having "darling smiles pasted on for eternity" shows the falseness and hypocrisy of such an ending. Sexton thus presents a challenge to fairy tales and the kind of "reality" they communicate, which has so little to do with real life.