This is Miss Betsey's estranged husband, whose name we never learn. Heartbroken and enraged, after separating from her husband, Miss Betsey drops his name and returns to her maiden name. We hear hints of him throughout the novel without knowing who he is. Mr. Dick tells David about seeing a strange man stopping Miss Betsey in the street and frightening her.
Later on, in London, Miss Betsey runs into this mysterious man while David is accompanying her. She doesn't explain until later that this is the cheat whom she married many years before. Even though he treated her so badly, Miss Betsey still gives him money now and then for old time's sake. Somehow, Uriah Heep finds out about this man. When Mr. Micawber, Traddles, and David all confront Uriah Heep with his wrongdoing, he threatens to set the law on Miss Betsey's husband if they don't leave him alone. But by this point, for better or for worse, Miss Betsey's husband has died, putting him beyond the reach of Uriah Heep's plots.