Please tell us all where it was debunked.
I don’t know if it was debunked straightforward but it is a bit flakey to me that this “mistress”, Madeline I think her name is, didn’t ever say things about this until 1989 or so.
https://en.wikipedia.org/wiki/Madeleine_Duncan_Brown
There’s so many people with stories that they can’t all be true. There’s the woman who claims she was LHO’s girlfriend in New Orleans.
http://mcadams.posc.mu.edu/judyth.htm
John McAdams, defender of the Warren Commission, anti-Conspiracy website: http://mcadams.posc.mu.edu/
JFK assassination forums are on the web too for those really interested: http://www.jfkassassinationforum.com/index.php?PHPSESSID=e88b942c81cd789a41b9263e901ef24b;www
You can start with this: http://www.dallasnews.com/news/news/2012/11/17/one-man-truth-squad-still-debunking-jfk-conspiracy-theories