From TV Tropes:
From the final episode of Mad Men. Transcript from Bustle:
“I messed everything up. I’m not the man you think I am,” Don whispers to Peggy, and it’s time he came clean to her about what he’s done so far in his life. Peggy, though, doesn’t realize what’s happening. She doesn’t know another Don Draper — she’s never met Dick Whitman. Don presses on, trying to explain to her who he really is. ”I broke all my vows. I scandalized my child. I took another man’s name. and made nothing of it.”
“That’s not true,” Peggy says back.