Jack only ever touches Ianto in moments of extreme stress/duress for both of them...reducing the dislocated shoulder in Fragments, the hand on the shoulder in EW when they're all trying to keep from bawling their eyes out, Jack hugging/kissing him in TSE when he thinks they're about to get blown to kingdom come by Daleks. Every other time I can see, Ianto initiates (a la Adrift, TTLM).