Mary Christmas
As I've come to realise, Mrs Claus is not Mary Chrismas. Mrs Claus is the proprietor of the Christmas Hotel in Whitby, and not the bride of Santa Claus, therefore, these characters need to be split.
These problems might be so great that the article's factual accuracy has been compromised. Talk about it here or check the revision history or Manual of Style for more information.
Mary Christmas, sometimes referred to as Mrs Claus, was the wife of Santa Claus.
One day Mary caught Santa with Iris Wildthyme on his sleigh and presumed that he was having an affair. Mary kicked Santa out and plotted to get her revenge on Iris for stealing her husband. Using Clockwork technology, Mary pulled Panda out of the time vortex and drugged him to find the location of Iris. Iris, however, had already found Mary and Iris regressed Mary's mind back to a time when she and Santa were happy and she let Santa move back in. (AUDIO: Iris Wildthyme and the Claws of Santa)
Mrs Claus and all her elves visited Iris' party in Hobbe's End in 1972. (PROSE: From Wildthyme with Love)
Other references
The Sto guide and supposed "Earthonomics" expert Copper claimed that human beings worshipped "the great god Santa, a creature with fearsome claws, and his wife Mary". (TV: Voyage of the Damned)
Behind the scenes
She was played by Judy Cornwell in Santa Claus: The Movie (1985), and voiced Robyn Moore in The Adventures of Candy Claus (1987), and by Pam Ferris in Saving Santa (2013).