“Not with a Bang,” Damon Knight, 1950 – A man and woman are all that remains of humanity. The man, a misogynist, cajoles the traumatized young woman into “marrying” him so that they might repopulate the earth. As he fantasizes about what he’ll do to her after he “has” her, the biological agent that has wiped out humanity with the help of atomic bombs and dust causes him to have an attack, paralyzing him in a bathroom that “bears the warning: MEN.” He realizes that the woman will not enter the men’s room to save him.
Comments: Also touches on racism. Read in The Classic Book of Science Fiction, ed. Conklin.
The Wikipedia review has a somewhat different take: “The story is an ironic, Adam-and-Eve tale. Humanity has been wiped out by a nuclear war, except for one man and woman, who meet in a restaurant in Salt Lake City. The man suffers from a disease that causes recurrent episodes of total paralysis. While in the bathroom, he has an attack, and dies with the realization that the woman is too prudish to enter and save him.”
Author: Wikipedia: “Damon Francis Knight (September 19, 1922 – April 15, 2002) was an American science fiction author, editor, critic and fan. His forte was short stories and he is widely acknowledged as having been a master of the genre.”