He smiled when she did because it was hard not to. Her smile was infectious. It was one of the things he really loved about her. She could always find a way to put a smile on his face, even if he was feeling horrible. If today wasn't proof of that, he didn't know what was.
Her words made his smile broaden. Sliding his arm around her shoulder, he pulled her in close and tipped his head to rest against the top of hers. "Well, that's good to know," he told her. "It would be quite awful if you were my girlfriend and didn't think about me at all," he teased.