And while Ben—who shares three kids with ex-wife Jennifer Garner—understands making art based on personal experiences, that didn't necessarily make the process easier.

"Jen was really inspired by this experience, which is how artists do their work," he shared. "They get inspired, their personal life. It moves you. I know as a writer and director, I certainly do the same things. But things that are private, I had always felt, are sacred and special because in part they're private. So, this was something of an adjustment for me."

The Greatest Love Story Never Told is available to watch on Prime Video now. And to look back at Bennifer's journey, keep reading.