How does Kennedy convey her portrait of this marriage?

In the story, Like a House on Fire, the narrator suffers from a serious back injury. The opening scene sets the emotional register: he must suffer the indignity of watching his and their eight-year-son get the Christmas tree from the lot to the car for the ride home while under the disapproving glare of the judgment of the salesman. Frustration mingles with anger and guilt kicks them both in the backside as his once vibrant state of wellness may be gone forever if he exerts and reinjures himself. Making the situation even worse is a search term he finds on his wife’s computer: “back pain psychosomatic.” “ From the text, we can infer that his wife speculates if the injury is all in his head.