Final answer:
The Duke in 'My Last Duchess' is driven by his need for control and his inflated pride, leading to the implication of his involvement in the Duchess's death.
Step-by-step explanation:
In Robert Browning's poem My Last Duchess, the primary motivator behind the Duke's words and actions is his obsessive desire for control. The Duke speaks to an emissary about a portrait of his former wife, revealing through his monologue his dissatisfaction with her independent spirit and his concern over her perceived lack of discrimination in bestowing her smiles. As the poem unfolds, it becomes evident that the Duke could not tolerate her refusal to live under his complete control, which ultimately leads to implications that he orchestrated her death. The Duke's need for dominance, combined with his inflated sense of pride and the value he places on his social status, essentially drives the narrative of the poem.