The 45-year-old actress has vented all of her frustrations and problems on paper since the age of 13, reported Contactmusic.
"Jen has been keeping journals since she was 13 years old. She considers them to be her therapy sessions. Jen had never mentioned her journals before, but she says there are six of them now," a source said.
"They're all simple leather diaries, locked away in a safe in her home. Every boyfriend, every relationship, her friendships, her work, her family - all of them are dissected on those pages," the source added.
"I think she finds it cathartic to write everything down in detail, get it off her chest, and then turn the page and move on," the source said.