[ That mixture of relief and disappointment seems to be contagious. On one hand he's relieved that she stepped back over the fence and into joke territory, but on the other... for just a brief moment it felt nice to entertain the idea. He's never done that before, never really had a reason to and now that it's rooted chances are he'll entertain it again.
Just not now. That was too sudden, too soon. ]
I like that. It sounds very... serious and legal-like.