At the end, did MTL have a sense of vindication

[RJNorton]

Where did Stackpole supposedly report this?

Apparently he told Ward Hill Lamon. The incident is described on p. 467 of Herndon's Informants. Herndon was taking notes on an interview he was conducting with Lamon, and Lamon reported that Stackpole had told him, "Mrs. Lincoln struck Mr. Lincoln in the face on a boat going to or at Richmond - struck him hard - damned him - cursed him." Unless there is another source all we have is Herndon's handwritten notes from this interview with Lamon. The interview is undated, but the book says 1865 or 1866.