Arthur opened the door to his wife's bedchamber, wishing only to calm himself with her kindness and gentle disposition. He had been closeted with some of the most recalcitrant of his barons and was tired. He stopped abruptly just inside the door-frame. Lancelot was sitting on Guenever's bed, and his shirt was off. Guenever and Lancelot's heads came up like frightened stags at the noise of Arthur's entry, their expressions full of guilt. They had not yet proceeded to any unpardonable activity, but the overfamiliarity of their situation was enough.
"Gwen—" he said helplessly, stupid with misery, "Lance—." And that was all before he turned to go. It was typical of Arthur that, when he saw the two people he loved best in the world betraying him with each other, his first thought was not to rage or seek retribution but to leave them to their happiness. It was for this reason, as much as any other, that he had tried so hard to forget Merlyn's warning given so many years ago.
Lancelot made no move to stop him, too caught in his own guilt and shame to be of any use. So it was left to Guenever, with her beautiful selfishness, to rescue them all.
"Arthur," she said, "stay," and he turned back and sat down. So simply was disaster averted.