Lonely People
He knows for sure that she's in love with him when she starts avoiding his touch.
It's not that he's a touchy-feely person, but even a broken man needs some sort of contact from time to time. He's only human after all, behind all his lies and elaborate masks.
Now he's trying to hold back for her sake. No more occasional brush of his fingers against her own when he brings her a mug of strong black coffee in the mornings; no more reaching for her elbow whenever he ushers her out of a room.
It makes him feel bleak and cold inside, and yet he owes her something for all the times she's stick to him through thick and thin. Lisbon is his best friend, and the last thing he wants to do is give her false hope.
He's not in love with her, probably never will. The only woman he's ever loved has been six feet under for the past decade, and his heart still belongs to her.
Angela wasn't a perfect woman, but he'd give everything in the world to have her back. The least he can do is keep his vows to her until his own death.