"Jack and I.... have a longstanding .... mutual...." He couldn't think of how to explain it all. At least, not in a way that would make her run for the edge of the roof again or take all night. "Agreement." That ought to do it.
"He stays out of my business, I stay out of his." His face twitched at the thought of Jack and his business. "So I suggest, ye stay out of mine." He growled, retreating again back towards the door.