Graves and Newt are somehow cursed so they can only be a certain distance from each other, or they end up being in extreme amounts of pain.

This of course does not work out very well when one is the Director of Magical Security and the other has a whole menagerie to take care of.

Bonus:
+ Graves taking Newt to important meetings, maybe with no explanation to those attending
+ The animals are smitten with Graves
+ Bed Sharing
+ Waking up snuggling
+ They're trying to figure out how to reverse it, but eventually it's kind of second nature to be very close