Every once and a while, they meet in one of the closed off interrogation rooms for lunch, because there isn't a chance of them being disturbed. John holds Olivia's hand lightly, absentmindedly, as if he's been doing it his whole life, and depending on how tired, how drained she is that day, Olivia rests her head comfortably on his shoulder.
It's different in that room, because in there, they're truly alone, instead of in some bar or crowded café, where they have to keep up some sort of appearance, whether they know someone there or not. Because in that interrogation room, where not a criminal or suspect has set foot in years, there's nothing wrong with a little cuddling, and they can get as close as they want to. The walls may be a dull gray, and it might be a little chilly, but that's fine by them, really. She can huddle in his arms to stay warm, and the only thing worth looking at to him in the world at that moment, can be her. That's the way it's meant to be, anyway.