Book Title?

[AnimalGirl]

I cannot remember the author or title of this book, but remember this summary: (romance)
An army widow with a very young son. She became a widow when her husband gave his bunk to a druken buddy & took the buddy's bunk only to be killed when the bunk was struck in a blast. The husband & wife had exchanged letters which the buddy finds & falls in love with the wife after reading the letters. He goes to find her & hopefully start a relationship with her without her finding out who he actually is (the man who got her husband killed). The buddy is known as a recklass, free-spirited man by the guys.
Thank you ahead of time for any help you're able to offer!

[musicman1956]

This sounds like the plot of the musical play "Martin Guerre". So I assume that's it.