The central conflict of "Shiloh" exists between the protagonist, Leroy Moffitt, and his wife, Norma Jean. Leroy has been in an accident that ended his career as a truck driver, and this means that he is home a lot more than he used to be. He is not used to being around so much, and Norma Jean isn't used to having him home all the time, and it seems to begin to create a strain on their relationship.
After Leroy's accident, Norma Jean began to attend a body-building class, and then she moves on to a writing class next. It's as though she is looking for excuses to avoid being around him all the time. In fact, "he can't tell what she feels about him." She's never complained of his extended absences, and she does not now "celebrate his permanent homecoming" in the way he wishes she would. He says that he wants to build her a new house, but she doesn't want it. It may be, he thinks, that "he reminds her too much of the early days of their marriage" when they had a child, a baby called Randy, who died at just four months old. Now that they are together all the time, like they were then, "they sometimes feel awkward around each other." Leroy feels like "they are waking up out of a dream together" and that they haven't really known each other all this time.
Eventually, Norma Jean insists that they "have started all over again" together, "and this is how it turned out." Their relationship just doesn't work anymore. It hasn't, really, in a long time, but the extent to which Leroy and Norma Jean were apart prevented either one from realizing it.