Old John was screwing an East German spy later in his life.
I know about the suspected spy in DC during WWII. Read about that in Reeves’ book “A Question of Character”
https://www.amazon.com/Question-Character-Life-John-Kennedy/dp/0029259657/ref=sr_1_1?crid=3KJIA3DQO81NM&dchild=1&keywords=a+question+of+character+thomas+reeves&qid=1607531648&sprefix=A+Question+of+Cha%2Caps%2C157&sr=8-1
I may have forgotten (Or not known) about that one. I will check the book.