Sorry to butt in. The way I see it Ianto tends to hold his real emotions inside & keep them private. I have the same tendency and when I suffered a similar emotional shock to EW the last thing I wanted was anyone to touch me, if they did I would have broken down & that was unacceptable. I think that Jack would know Ianto well enough at this point to know that Ianto wouldn't appreciate having his feelings on display like that - hence no big clinging, hugging weeping scene in EW.
But that just my opinion and is worth something only to me.

Morgan