Final answer:
The character being described is Myrtle Wilson from 'The Great Gatsby,' a lower-class woman who has an affair with Tom Buchanan and experiences a brief sense of empowerment before meeting a tragic end.
Step-by-step explanation:
The character description provided points to a character in F. Scott Fitzgerald's novel 'The Great Gatsby,' who is none other than Myrtle Wilson. She is indeed the married lover of Tom Buchanan and represents the lower class in sharp contrast to the opulence of the wealthy characters. Myrtle seeks to improve her social standing by engaging in an affair with Tom, which gives her a taste of the upper-class life she so desperately desires. This liaison allows her an escape from her own mundane and unfulfilled life, and she revels in the temporary power and freedom it affords her. However, her aspirations and her secret life lead to a tragic end, as the question hints, when she is struck and killed by a car driven by Daisy Buchanan, Tom's wife.