One of the things I like about Ianto is that he doesn't seem to push Jack to open up and because of that Jack does.
It's one of the things that annoys me about Gwen, she does that stereotypical manipulative woman thing sometimes, as in "No-one else will have me," where she kind of issues these below the belt challenges at him to talk to her. I love how he sidesteps those and never answers one way or the other.