Simply put, life can change quickly. And former Flyleaf frontwoman Lacey Sturm is now speaking about some of the life-altering reasons for her exit from the hit-making rock band in a new video promoting her upcoming book, 'The Reason: How I Discovered a Life Worth Living.'

The book is due Oct. 7 via Baker Books and Sturm has issued a couple of videos to promote the effort. The previous clip delved into her reasons for writing a book, while this new video focuses on her decision to leave the band.

Sturm says in the video, featured above, "We were on our second album when I got married. And the album was called 'Memento Mori.' And 'memento mori' means remember you're mortal, remember that you'll die and remember that your life is short and precious and so are the lives of those around you."

The singer says that idea stuck with her as she went through some very life-changing events, including marriage, starting a new family and suffering the death of the band's close friend and sound engineer Rich Caldwell.

She recalls, "We had a few things happen that really brought that message home, but the one that hit the hardest was the death of our sound engineer. We did one last show with Flyleaf as a benefit for his wife Katy and their son Kirby. And it was really hard to do a show without him, and it was really hard to think it could be our last show. So I remember looking at my son after Rich had passed and just wondering to myself, if this was the last year I had with my son, how would I spend it?"

The combination of events all played into her decision, and she adds, "It was really amazing to recognize this season changing in my life and the freedom that I was gonna be able to focus on my family. And I'm so thankful for that time. And although it was really hard, I'm thankful. And that's the reason I stepped down from Flyleaf."

To learn more about Sturm's upcoming book and see her video discussing the project, click on the button below. The page-turner is currently available for pre-order at Amazon, iTunes and Barnes & Noble ahead of its Oct. 7 release.