By the time Charles Dickens had grown tired of his wife, the couple had 10 children and Dickens was a rich and famous man. The two separated, unhappily and against Catherine’s will, and Dickens published a notice in the newspapers declaring her an unfit mother. She was sent away to live alone in shame, and her sister moved in to help Charles with all those kids.

These sad details of a disintegrating marriage are rich fodder for fiction, and Gaynor Arnold has done a wonderful job picking up where the facts leave off and telling the story through the wife’s point of view.

In her novel “Girl in a Blue Dress” (Crown, $25.99), the names are changed to Dorothea and Alfred, but there is no mistaking whom Arnold is really writing about. The book opens on a day of national mourning — Alfred’s funeral, with Dorothea grieving alone, estranged from her children and ashamed to be seen in public. As the novel progresses, the story line shifts from the sad present to the ecstatic past — their courtship and happy early years. Alfred was a vibrant, exciting man — vain, yes, and always the center of attention, but also someone who elicited joy and laughter wherever he went. Dorothea, sweet, shy, alluring in a low-cut blue dress, wins his heart.

Arnold’s compelling, historically true novel makes sense of the rise and fall of the marriage, and of the devotion that Dorothea felt for her husband, who treated her so badly but never lost her love.