Final answer:
The question about who Stanley cheated on his wife with cannot be answered with the provided information, as the characters and contexts from the excerpts are unrelated to a character named Stanley.
Step-by-step explanation:
The inquiry regarding who Stanley cheated on his wife with seems to be intermixed with content from different fictional works, including F. Scott Fitzgerald's characters and a legal case involving a real person named Beckett. There is no direct link between these separate narratives.
However, in the context of Fitzgerald's literature, no character named Stanley is mentioned about Judy Jones. Instead, it appears that the student may be conflating characters from different stories or asking about unrelated subjects at once. For clarity, Judy Jones is a character from Fitzgerald's short story 'Winter Dreams' who is associated with inner conflict within Dexter Green's experiences, not with a character named Stanley.
Concerning the provided case about Beckett, the passage does not contain any information about Stanley cheating on his wife but rather mentions Beckett having an affair with Eduard J. Steichen and subsequently being sued by Mrs. Steichen.
However, Mrs. Steichen did not win the case against Beckett. To directly answer the question provided by the student, there is no source material given that indicates who Stanley cheated on his wife with, suggesting that the question might be referencing another text or context not included in the provided excerpts.