Self harm is probably one of Tony's calling cards. And yes on the detachment. He can;t escape from his life / job / mistakes physically, so he must distance himself emotionally, or else risk being overwhelmed and lost in his own sea of misery and self pity / loathing.

But what he truly never understood was that if he HAD showed all of that internal hurt, Steve totally would have cuddled him better (hopefully in the nude); much to the delight of the fangirls.