Damon would have been a liar if he'd said that Katherine's leaving was anything but the pleasure it truly was. Honesty might not have been his strong suit, but he could play the game when he chose. Closer to the truth, though, was the fact that her presence was most disconcerting in those unguarded moments when memories blurred, and his heart did its own thinking - always a dangerous thing - and he forgot the myriad reasons why he no longer loved her.
On the other hand, staying here and watching Stefan and Elena together was its own exquisite form of torment. But he wasn't about to give either one of them the satisfaction of knowing that they possessed such a power over him. No way.
So he flashed his brother his most charming smile, and airily replied, "No one I can think of at the moment, brother dear." And he settled himself for the show that was surely about to begin. Perhaps even the End of Stefan and Elena Show. For that, he most assuredly wished to keep his ringside seat.