After the narrator killed his lover, he "propped her head up as before,/Only, this time my shoulder bore", and then sits like that, in semblance of a happy couple, happy that she is his forever. He does this so that he can possess her completely.
The narrator is a man who is highly jealous and possessive, and bitter about his love's time being spent elsewhere. He doesn't answer her call when she arrives; so, he is pouting. He is upset that her heart is "Too weak, for all her heart’s endeavor/To set its struggling passion free/From pride, and vainer ties dissever,/And give herself to me forever". He wants her to reject all else and be with him, but she does not, is too weak. So, he takes matters (or, her hair) into his own hands and fixes it so that she can be.
Dramatic monologue is where a speaker tells a story, often in poem form. The only perspective we get is of the narrator's view of events-they are the only one speaking. The above quoted passage sounds like natural speech; it is so bitter in expression, different from the detached feel of the rest of the poem, so the emotion was so powerful that it probably came through in a more natural form, overhwhelming the calmness of the rest of it.
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Browning's "porphyria's lover" has Hamletian touch.In this poem we find the abnormal psychology of the lover .He think that he has fulfilled the desire of his mistress who wishes a happy death in his lap .In the climax of the amorous moment , he wants to make the moment eternity .He had no evil desire , and the lady-love slowly and gladly has passed into the word of silence .During the fastening , her countenance did not show any symptom of pain .Her eyes were as fresh as they could be .
The poem speaks of strange kind of love .Browning's lovers are every where peculiar in their attitude to love .The Duke in , My Last Duchess , the rejected lover in The Last Ride Together , the lady in the laboratory ,-are all more or less abnormal .In the province of human psychology the question of normal and abnormal does not arise .One man , from his physic point of view ,is totally different from the other .
The lover in this dramatic monologue , after killing the lady waits whole the night for the approval of God .God through His silence approves the deed .For , we may take for granted that God wants Porphyria in heaven , and the lover would in the immediate future would visit heaven . In heaven , they will be free to enjoy each other .