Max Mallowan

After the events that happened at Eddison Manor in 1926, Donna Noble asked the Tenth Doctor if she would be "okay". He replied that she would be fine, that she would go on marry again, to a second husband, and write more books. (TV: The Unicorn and the Wasp)

Behind the scenes
While not named in TV: The Unicorn and the Wasp, Agatha Christie's second husband was famous archeologist.