Lyric discussion by Reginald Edit 

One addition/correction to my theory:

The house (not a home) in the end is the one he is leaving. It is easier to leave it if it is only a house and not a home.

To add to Reg's notes he's not "just" cheating. The song expresses unhappiness and sadness about his home life. It may be an affair, he may even be leaving permanently: "from here to the moon" "How things can change, I know" "Try to pretend, it's not only ... Glass and concrete and stone" And I think the use of a name, here "Harriet Hendershot" and her wearing sunglasses suggests that it's someone the neighborhood would recognize.

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