"Today, I have a choice. I can bury myself under the covers and acknowledge the pain of missing you and mourn the future anniversaries without you. Or, I can celebrate never having a day without you in my heart because you loved me enough to leave me a lifetime of memories and beauty."

Those are some the words penned by Taya Kyle on March 17, the day that would've marked 13 years of marriage to her husband, the late Navy SEAL Chris Kyle.

Kyle, who was credited with being the most lethal sniper in U.S. history, was shot and killed at a Texas gun range in 2013. His life story became the subject of the Clint Eastwood film "American Sniper," which was based on the best-selling autobiography of the same name.

To mark their wedding anniversary, Taya posted the poignant love letter on Facebook. It has since gone viral, with more than 530,000 likes.

Read it here: