An older book much enjoyed

[AnimalGirl]

I remember the summary of this book and was curious if anyone would recognize it as I've forgotten the author/title. It is fiction, romance:
It's about an army widow with an infant and she became a widow when her husband gave his bunk to a drunken buddy and took the buddies bunk only to be killed when the bunk was struck in a blast. The husband and wife had exchanged letters which the buddy later finds, reads and falls in love with the wife through. He goes to find her and hopfully start a relaionship with her without her finding out who he actually is (the man who got her husband killed).
If you have any ideas, please let me know! Thanks!