still searching for a female bestselling author who served jail time for killing her husband . english/canad?

Answer 1

Would it be James Tiptree (yes, she's a female; that was her pen name)
"t was in college that I began to discover some of the women authors that were Tiptree’s contemporaries, such as Ursula K. LeGuin and later Joanna Russ and Marge Piercy – as well as Tiptree himself … er, herself. I originally sought out Tiptree after reading about the woman author with the male pen name who killed her husband and then killed herself in 1987, the year I graduated high school."

A critically acclaimed science fiction author, who wrote under the pen name James Tiptree Jr., killed her husband and herself today after warning her lawyer to call the police, the authorities said.

A critically acclaimed science fiction author, who wrote under the pen name James Tiptree Jr., killed her husband and herself today after warning her lawyer to call the police, the authorities said.
Alice Sheldon, 71, and her husband Huntington Sheldon, 84, were found in bed together with single gunshot wounds to their upper bodies, said officials of the Fairfax County police."

But she didn't serve any jail time.

Answer 2

are you talking about the scarsdale diet doctor ...herb tarnower and the lady from ohio?