And Jack - with the possible exception only of Spike - is probably the best person he could work through it with. Like Spike, he's careful in the extreme of his partner, and Ianto especially because everything matters so much with him. Especially after what they've been through recently.
"I'm glad you feel you can trust me with that," he says, rather humbly, and then adds diffidently, because he feels it really bears bringing up in light of recent conversations: "As long as you feel confident in saying no to me if you find you need to?"