Sal went back to his aunt’s house to rest. His aunt told him he was wasting his time with Dean, but Sal wanted to “take one more magnificent trip to the West Coast.” He says that he wanted to see what Dean would do and also wanted “to have an affair with Marylou,” since he knew Dean would get back together with Camille.
It’s no surprise that Sal’s aunt—a part of the “normal” world— doesn’t approve of Dean, or that Sal doesn’t listen to her. But it is interesting that Sal has discrete reasons for wanting to go: that this will be his last such trip, or that he wants to get with Marylou. Dean doesn’t have reasons like that: he just lives recklessly. Again this point to a difference between Sal and Dean, and a sense that Sal is in it for the experience while Dean is in it because there’s no other way for him.
Before Sal, Dean, Marylou, and Ed left, Carlo talked to them in his apartment and asked what they were all doing with their lives. He warned them that their vagabond lives would soon fall apart. Sal and his friends stayed at Carlo’s apartment for a while. Ed walked around Times Square one night and suddenly thought that he was his own ghost, walking on the sidewalk.
One day, Dean asked Sal for a favor. In a “hoodlum bar,” he asked Sal to “work Marylou,” i.e. sleep with her. Sal thought Dean “wanted to see what Marylou was like with another man.” Dean and Sal went back to Carlo’s apartment and told Marylou their plan.
Dean and Sal make the plan for Sal to sleep with Marylou without consulting her—they treat women as playthings. Marylou threatens to come between Sal and Dean as friends.
Sal couldn’t go through with it while Dean was watching, so he asked Dean to go into the other room. Sal whispered to Marylou that they should wait until they were “lovers in San Francisco.” He left the room and sent Dean back to Marylou. Sal thought about Dean’s time in prison and how he had never seen his mother. He concluded that he “didn’t want to interfere,” in Dean’s “complete love of his Marylou.”
Usually not shy with women, Sal values his friendship with Dean so much and cares for Dean so much that he doesn’t want to come between Marylou and him.
Carlo came back to the apartment, upset at “jam on the floor, pants, dresses thrown around, cigarette butts, dirty dishes, open books.” Sal saw that “Marylou was black and blue from a fight with Dean about something,” and knew “it was time to go.” Before leaving, he collected his things from his aunt’s house and called Old Bull Lee in New Orleans, who was fed up with Galatea staying there, waiting for Ed. Sal told his aunt he’d be back in two weeks and then took off west again.
Carlo is beginning to get fed up with Dean and Sal’s irresponsible behavior. While Dean has been inconsiderate to both Marylou and Camille in the past, this is the first time we see evidence of him physically abusing Marylou. When things get bad, Sal realizes they have stayed in New York long enough and should get on the road. The road—moving—always seems to be the cure.