We were reading different books all the time; we never knew it until you shut yours and I shut mine.
We were reading different books; well, what of it? You liked yours— I wrote mine and I love it.
Two people sit side by side, each absorbed in a book, and neither realizes the other is reading something entirely different. Only when both books close does the truth come out. It works as a small, quiet picture of a relationship in which two people share space and time but not the same inner world.
The second stanza is where the poem turns. The speaker repeats the opening line, then shrugs it off with "well, what of it?" That brisk, almost defiant tone suggests she has stopped mourning the gap. The final contrast is the sharpest part: the other person merely *liked* a book, while the speaker *wrote* hers and *loves* it. She is the author, not just a reader. The mood moves from gentle surprise to dry, confident independence. There's a faint sting underneath, but what the speaker mostly feels is self-possession, a calm pride in her own story.