I read my friend's private notebook and changed my behaviour. Do I owe her the reason?

My friend left a yellow notebook open on her kitchen counter while she went to collect a delivery. I saw my name in the middle of the page. Then I leaned closer and read the rest.

She'd written that I turn her stories back to myself. There was an example: she'd been telling me about a difficult conversation with her dad, and I'd interrupted with a story about mine. I remembered doing it. I hadn't thought of it as taking over until I saw how she'd described the evening.

Over the next few weeks I made an effort to stop. I let her finish. I asked about things she'd told me before. Last night she said our catch-ups had felt really good lately.

Now the improvement feels tangled up with something I had no business reading. If I confess, she'll know that a private page on her own counter wasn't private around me. If I don't, I keep accepting thanks for a change whose source I'm concealing.

I only read that page, but 'only' sounds like a word I'm using to get out of trouble. Is there a way to own the snooping without making her defend what she wrote about me?