Lex celebrated his happiness by running on the treadmill for about an hour and a half. That sufficiently wore down his urge to jump around and shout with joy. He hadn't slept with Lana. That simple fact just made him feel so good about life that he wanted to run on the treadmill some more. Instead he took a shower and went to his office to play pool against no one.
It was only then that he realized what a close call it had really been. Quietly he lay down the pool cue, considering that fact, and understood then that there was nothing to celebrate about. He had made the monumentally stupid mistake of letting himself get close enough to worry. He'd lost control, and that was unacceptable. The fact that he had actually had to wonder whether or not he slept with her told him that his level of self-control was becoming dangerously low. There should have been no mistake. He shouldn't have been drinking, he shouldn't have let her in the house, he shouldn't have kissed her, and after all that, he shouldn't have been thinking about her in the first place. She was fifteen, for Christ's sake. He could have any woman he wanted. "Don't choose one that's going to get you into trouble," he murmured.
He worked his jaw pensively, and silently agreed to keep himself in line. He had been getting lax in this soft, corn-sodden Everytown. Things had to change, or he was going to hurt his business here. Or Clark, his brain told him, but he made a conscious decision not to think about that. That would put him on a whole new train of thought, one that was harder to control than business, one that hurt. It wasn't like he had a lot of experience in having friends to hurt. There were some new things he didn't have to try. He picked up the pool cue again, a harder Lex Luthor, or at least a Lex Luthor trying to be harder. He dismissed his lingering thoughts of Lana as juvenile and borne out of unhealthy boredom, as he dismissed most of his thoughts and feelings.