I have also used Google docs with previous subs - you can create chapter markers for each entry, contents etc. or just keep as one long flow. One of my partner's even included pics of places she'd visited or poignant memories so it became a beautiful multimedia log of her innermost thoughts.
As a Read more… Dom, I feel the delicious privilege of being included in such an insight irrespective of the quality and it can be playful to steer/correct my sub as if like a school teacher - depending on the dynamic.