"If we had to fight the dead on top of vicious storms I feel that even though you and I would be uniquely qualified for such a thing, it would bring back memories we would rather not have," Sansa says.

"Worrying for a threat that has not yet arrived upon your doorstep is harrowing enough. I cannot imagine fighting one for myself."

It is a lie; Sansa has fought the dead and seen them but she is protecting Jon from a future he doesn't know about. He deserves that much.