Sex is one of those "earthly" things that travelers like the seafarer just can't take pleasure in, despite the fact that all those "city-dwellers" seem to be able to. He calls it "pleasure in woman" (45) and says it's "not for him." That's the only mention of sex in the poem. Some scholars believe that "The Seafarer" is recommending that people live like monks, in which case sex is a big no-no. If that's true, it explains why the poem rejects all kinds of earthly pleasures, sex among them.