As soon as Cain felt the touch on his leg, he reached out and placed his own hand atop David's, wanting to keep it there. David might think he didn't want to be touched, but Cain couldn't switch his feelings for the vampire off like a faucet, and he was yearning for their connection to be re-established. Subconsciously he was wanting David to rethink himself, to change his mind again, to decide that keeping Cain around was a good thing, for both of them. Fuck, Cain wouldn't even care (too much) if David had this other guy as well, as long as Cain got to continue having the type of relationship with him that he wanted.
"I thought you meant other guys, not another guy," Cain explained, but it didn't really matter now. He lowered his gaze to look at David's hand upon his thigh, and his own one holding it, and soon both of his hands were holding David's one, and he squeezed it between both of his, knowing that when David walked out his door again he would be gone, so he'd just hold on a little longer, to keep him around that little bit extra.
"It's okay," he said finally, because it was in him to attend to David's needs, for he was the superior and shouldn't feel bad for it. Cain was in conflict, for he both wanted David to feel ashamed and he also wanted to make him feel better. His accomodating nature won out, for it was the most prevalent. "I get it. I mean, I told you straight up I wasn't special enough. Not as special as him, I mean," he clarified, not wanting to be told that he was special, not now, not when David was proving in his actions that Cain really wasn't good enough.