It's almost funny, that the facts about biochemistry and the relationship between hormones and pair-bonding stay firmly at the back of his mind where they belong. That she can always seem to find a way in past his genius to a part of him that simply cares too much to deflect something of real importance.

"I love you," he murmurs. Which is itself a statement of fact, just not one meant to break the heady power of the moment they're sharing.