I usually "live" in a journal for a few months before all the pages are full enough to move on to a new journal. In the process pages get wet and heavy. They loosen up in my journal. Sometimes the pages shift in the book from the weight of heavy paints and gesso.
To keep the pages in place I wrap several pieces of string every 10 or so pages and tie them as tight as I can against the spine. This holds the pages in place.. To make it all look pretty, I tie additional scraps of ribbon to each string. Over time, each string will be tied with 10-20 little bits of ribbon and string. I like to use ribbon that I find along the way...birthday gift ribbon, string from packaging, scraps of fabric, etc. .
What emerges is this wild, rich journal, filled with stories, images and bits of fabric from the journey in your journal.