Left for dead in the chaos of war torn Europe, Allied victory would have done nothing to help Mrs. Dover's fiancee recover from dislocation in his desperate post-war environment. Returning home would be difficult for anyone under such circumstances, especially if they were at least temporarily taken prisoner. Lost in a foreign and unfriendly country, consumed by the horrors of war, and considered nonexistent by his own country and (to her relief) fiancee, the vengeful and obsessive mentality that Mrs. Dover's fiancee exhibits is understandable even without consideration of his original mindset. Mrs. Dover's vivid memories of her fiancees personality--the only thing which she can wholly remember about him--are less than endearing, to both her and her family he came off as an unfeeling man who fancied her for reasons less noble and more pragmatic than love "He was set on me, that was what it was--not love (page 163). Although this portrays her fiancee as a cold and obviously undesirable bachelor, Mrs. Dover was still the perfect suitor; hence her latter marriage with Mr. Dover.
Despite considering her engagement "a sinister trough (page 162)", the reason--the reason that should could not seem to recall--that Kathleen was still set on her fiancee was because of his almost superhuman sense of commitment. As her failure to attract men latter proved, commitment and dependability were the only admirable traits that Kathleen could offer as a spouse. Thus dependability, not romance, became ""the keystone of her family life (page 163)" with Mr. Dover. Having promised Kathleen that he would eventually return from deployment and that the only thing she do in return for his word is simply wait, and seeing Kathleen betray this commitment,even if years after the fact, would have embittered the forgotten veteran even further. Weather in love with her or not, his vow turned Kathleen into his primary inspiration to survive the war and return home. Unable to simply strike against his own government for abandoning him and obviously unwilling to fight its old enemy's once again, Mrs. Dover became an outlet of catharsis to vent his resentment against.
Even if betrayed 25 years afterwards, Kathleen's fiancee still knew that commitment was her driving characteristic, making his basis basis for how the murder plot should be executed; dependability had prompted Kathleen into into her engagement just as it compelled her return to her pre-war home. Knowing this, Kathleen's fiancee used of the chaos and dispersement of The Second World War to make his move on Mrs. Dover. Whereas