In Iron Man #59, we learn what's happened to Marianne Rodgers:

Does Tony take this well? I'll give you one guess.

(Click the jump for more!)

Here, Tony blames his difficulties with intimacy on the armor. And yes, it's highly likely that his extended inability to touch and cuddle his dates was psychologically damaging. But I think the problem runs deeper than his metal chest plate -- or the other excuses he uses to push people away. I think the problem is rooted in a deep-seated fear that opening up will cause him to lose control of his own very strong emotions. (Remember: the above sequence is hardly the first time - nor the last - that Tony has exploded and trashed a room.)

Addendum:

This makes me laugh so much. Tony "redecorating" a room while his friends outside boggle is such a classic Iron Man motif.