You see, I'm not sure whether this was Booth's not-so-tactful way of 'acting' detached, so that things don't get hard for him, or if he was just being detached for real. If the former is the case, I guess, I won't hold anything against him. He is just trying to guard himself, and trying to protect a relationship that has made him happy. But if the latter is the case, God help him then :@
But I think the first one is more likely. Not only does it somewhat go with the Booth we love, but also the recent spoiler said that Brennan will always be Booth's pillar......so, I suppose he is just trying to act detached so that his feelings for Brennan does not come in the way of his relationship with Hannah, and more importantly does not hurt him all over again.