A Girl to Come Home To (Musaicum Romance Classics). Grace Livingston Hill

Rodney Graeme is a war hero. When he returns home, the whole town comes to greet him. Everyone including his sweetheart Jessica, who had left him for a richer man while he was away. Jessica's husband is now using Rodney's feelings for his wife to his own advantage and all of a sudden Rodney finds himself caught up in an espionage plot.