It wasn't that Jack was upset. Jack didn't usually get upset. He did, however, have his pride and the moment York's hand connected with Ianto's arse, that pride became rather wounded. There was a hint of possession in that action, the same Jack had shown when Ianto leaned against his leg earlier.
There was that nagging bit in the back of his mind that had wondered if Ianto had moved on. That familiarity told Jack all he needed to know.
And Jack didn't like it one iota. He was torn between two warring factions: the one that wanted to throttle York and the other that wouldn't mind having York up against a wall. Right now, Jack wasn't sure which side was going to win out. He drew his lips into a thin line, eyes flicking back and forth between Ianto and York, looking rather unamused as he reached for his coffee mug.
"I haven't either but then again I just got here about a week ago," Jack replied. He returned his gaze towards York, attempting to keep his expression light, eyes focusing on his face and then his chest. Keep his eyes trained on York that way he didn't have to see where York's hands were on Ianto.
"Don't worry, love," Jack said, winking at Tonks and glad for the distraction, "we won't leave you out of any orgy that may happen to occur." He slid forward on the couch, reaching for another set of papers, flipping through them and punching things into his wrist strap. Nothing, however, was making sense. "With our new friends," Jack said, emphasizing the word, "How many of you lot chose to be here and how many were sucked here by various means out of your control?"