Marie Tillman kept the letter hidden at the bottom of a bedroom drawer where it lay untouched through his first two tours in Iraq. He was killed by friendly fire in Afghanistan in 2004.
When she received the news of her 27-year-old husband's death, she went looking for the letter that she had hoped never to open.
Her book about the couple's 11-year relationship from high school sweethearts to his untimely death The Letter: My Journey Through Love, Loss, & Life is out on Tuesday.
The handwritten pages were in a familiar scrawl from her husband, whom she began dating during their senior year of high school in San Jose, California.
It read: 'It’s difficult to summarize 10 years together, my love for you, my hopes for your future, and pretend to be dead all at the same time . . . I simply cannot put all this into words. I’m not ready, willing or able.'
The book tells how 'painfully shy' Marie first noticed that the high school football player had a crush on her when he fell silent when she was around.
It tells the story of their love affair through the notes that the NFL star wrote his wife from the moment they met as teenagers, according to the New York Post.
Letter writing became central to their relationship early on after Pat Tillman was placed in juvenile detention for a month following an arrest for a teenage fight.
'Hi dude,' he started a letter at the time.
'I am glad I got a chance to see you. Actually glad is really not the word, but the less I think about it the easier it is.'
The couple remained together when they attended different colleges - she went to the University of California and he took a football scholarship at Arizona State - and letter writing became even more important to them.
When they graduated in 1998, Marie went to join Tillman in Arizona where he had been drafted to the NFL as a safety for the Cardinals.
However following 9/11, she explained that there was a shift in how he viewed the world and felt it was his duty to serve his country.
He gave up his NFL career - and a $3.6million football contract - to become an Army Ranger. The couple moved to a base near Seattle and married soon afterwards.
The two decided to put off having children after he enlisted and planned to start a family when he was finished service.
When Mr Tillman was deployed just two months later, the letters began coming thick and fast.
In one he wrote: 'I know this isn’t the life you dream to live... And I know at times you’ll feel alone... I know we have each other and I love you.'
The letters contain detailed plans that Mr Tillman had for the couple's future and his fear at the decision to leave his wife alone while he served in Iraq and later Afghanistan.
His also wrote about the difficulty of war and the challenges that soldiers faced on the frontline.
It’s difficult to summarize 10 years together, my love for you, my hopes for your future, and pretend to be dead all at the same time . . . I simply cannot put all this into words. I’m not ready, willing or able.
Pat Tillman's final letter to
Marie keeps the letters in a shoebox at the bottom of her wardrobe.
Mrs Tillman, who was only 27 at the time of her husband's death, spent years grieving and reread the letters so many times that she has committed them to memory.
Although she keeps most of her late husband's final letter a secret, she does reveal one important paragraph - where he tells her in the event of his death that she must move on with her life.
Last year, Mrs Tillman, now 35, met Joe Shenton, a divorced father-of-three. After a whirlwind romance, the couple wed in September 2011.
Mrs Tillman told how the investment bank director did not just see her as the widow of an American war hero. ‘We had this instant connection. I felt like he just saw me,’ she said.
Soon the couple were ‘talking on the phone for two to three hours every night – we just fell in love,’ the 39-year-old added.
Mrs Tillman, who gave birth to son Mac Patrick in January, lives in Chicago and continues to work for veterans through the Pat Tillman Foundation.
Read more: http://www.dailymail.co.uk/news/article-2163906/Pat-Tillman-Widows-book-tells-NFL-stars-love-letter-following-death-friendly-Afghanistan.html#ixzz1yntcV075