The pressure kind of closed in quickly and I think Romo thought the blocker (couldn't see who) would stand up his guy and he got hit when he threw it. It wasn't the best decision (I don't think it was anywhere near as bad as the Reed INT from last season), but he shouldn't have thrown it in that area because the WR was pretty much covered. If Romo didn't get hit, there's a decent chance the ball would not have been picked off. The silver lining in this (IMO) is that Romo reportedly stated he was mad at himself for making a bad decision. Again, it wasn't the worst decision in my eyes and he did get hit throwing the ball, but I like the fact that now he sees that as an unacceptable decision where in the past he would just shrug it off like that comes with him being a big play QB.
Baby steps, baby steps.
YAKUZA