Rikon Suru Tsumori datta.

Bernard, the heir to a fallen viscount family, had lived like a commoner since before the war. Two years after being drafted and fighting on the battlefield, unable to return home, he receives a letter from his mother. "You have recently gotten married." He doesn't know the name or face of his new wife, Cherry, and has never even met her. With no guarantee that he will return alive, this long-distance marriage should be ended as soon as possible—in other words, he writes a reply requesting a divorce. A month later, the letter from his wife contained only one line: "Isn't it enough if you don't die?" Source: MU