This is where we get to that crazy-making part. I look at "are you going back to him," "partners in what way," "Jack needs me," the coat nuzzling, glaring at Martha while Jack was sparkling, "would you go back to your own time," cutting in on Jack/Gwen dancing, etc etc as whining, clinging etc and can't for the life of me see how anybody doesn't see it the exact same way, especially when it's still going on in The Stolen Earth.

Which is why, even thought I hope and pray that "threeseome," really means "threesome," I just can't imagine Ianto given up what he perceives as sole possession of Jack's body and soul very easily.