At the end, did MTL have a sense of vindication

[L Verge]

And speaking of Mrs. Lincoln's personality. a gentleman wrote to me today and mentioned again something that I had asked about previously on this forum. Is it true that Mrs. Lincoln slapped her husband on the way back upriver on the River Queen?

My correspondent quoted from Michael Burlingame: "On April 9 [1865]...Thomas Stackpole, a White House steward, reported that on the trip back to Washington, the first lady struck her husband in the face, damned him and cursed him. At a dinner party aboard ship, Mary Lincoln's seamstress, Elizabeth Keckly, observed a young captain, 'by way of pleasantry; say: 'Mrs. Lincoln, you should have seen the president the other day, on his triumphal entry into Richmond. He was the cynosure of all eyes. The ladies kissed their hands to him, and greeted him with the waving of handkerchiefs. He is quite a hero when surrounded by pretty young ladies.'"
Burlingame goes on to say that "Mrs. Lincoln turned to him with flashing eyes, with the remark that his familiarity was offensive to her. Quite a scene followed."

Has anyone seen such a report on the slapping - other than from Burlingame? Where did Stackpole supposedly report this?