Christopher Manley: The look that Pete gives Peggy is, ‘You could have been the one. I could have grown old with you.’
Matthew Weiner: I can’t even put into words what that look is. We wrote it in there that they look at each other and they acknowledge it. That she sees him with those guys and he sees her with those guys, but they’re both content where they are. I think that’s sort of part of it, too, right? They’re connected—they’ll be connected forever.
Audio Commentary, Mad Men 4x04 “The Rejected”