Are those stories about Mary abusive to Abraham overstated???

[RJNorton]

Quoting Professor Burlingame:

"The abuse didn't end once the Lincolns got to Washington."

"She would regularly — we have testimony from more than one source — she would insult him. She would berate him in front of other people, and say, 'That's the worst speech I've ever heard anybody give. I don't see how a man could get up in front of the public and speak such venal things," says Burlingame, who's readying a monograph on the Lincoln marriage. "And if she does that in front of other people, what does she do in the privacy of her own home? Or in this case, the White House?"

Does anyone know Burlingame's original source for Mary's comment on Abraham Lincoln's speech?

https://history.howstuffworks.com/histor...incoln.htm