Answer:
The stopped in the Valley of Ashes on their way to the city to meet Tom's girl, his mistress Myrtle Wilson.
Nick felt he had been ambushed or forced to meet her even though he had expressed no desire to be acquainted with her.
Explanation:
F. Scott Fitzgerald's "The Great Gatsby" revolves around the story of Jay Gatsby and his desire to reunite with his former girl friend Daisy Buchanan. The story deals with themes of wealth, social life, a lost American Dream, love, life, etc.
The narrator Nick Carraway mentioned how he met Tom Buchanan's mistress in Chapter 2. Tom has been married to Daisy for several years now and his mistress Myrtle is also married to George Wilson. When Tom took Nick to meet Myrtle, it was more of a forced invitation rather than a request. Nick recalls how Tom was <em>"taking hold of [his] elbow literally forced [him] from the car."</em> Nick seems angry about the whole thing, <em>"The supercilious assumption was that on Sunday afternoon I had nothing better to do."</em>
So, Tom and Nick stopped to meet Myrtle Wilson, Tom's mistress. Nick feels that it was more of a forced meet rather than a request to make him acquainted with her.