I listened with heart fit to break. (5)
The speaker's passivity at the beginning of the poem is pretty extreme. His only response to the storm is to "listen," even though listening makes his heart break.
And kneeled and made the cheerless grate Blaze up, and all the cottage warm; (8-9)
Porphyria, on the other hand, has more agency and activity than the speaker can handle – she's able to make the fireplace "blaze up," apparently without even lighting a match! She's the opposite of passive.
And last, she sat down by my side And called me. When no voice replied, (14-15)
The speaker can't even be bothered to answer Porphyria when she calls to him. And he doesn't even say, "I didn't answer" – he just notes, "no voice replied."