I suspect there is a bit more to the story. Once it was known, the affair was no longer any kind of a security problem so that cause is out. It is not unlike that homosexual with a top secret clearance during the Johnson administration. It is like Clinton with his little chubby bimbo under the desk. No problem at all once the "devil with the blue dress" turned over the blue dress. How do you blackmail a guy for something everybody already knows?