You are NOT an idiot for wondering wtf he was doing when he was not home from a 7:30 meeting by 10:30! First of all, as you say, trust takes time to rebuild. Just b/c he SAYS he is doing so and so certainly doesn't mean it's true, based on past experiences, right?
Second, why the hell didn't he call you and tell you about this change in plans? Seems to me that would have been the responsible thing to do. So yeah, I wouldn't be so certain that just b/c he says he is not drinking, he really is not. This behavior is not right, to me.
This behavior isn't mature or considerate, and don't bend over backwards making excuses for him. One of the first things I learned to do here was not listen to what my AH
said, but pay attention to what he
did.
He said all the right things, had all the right stories. He apologized and nodded and laughed at the right times. But he still disappeared, still had weird explanations for why he couldn't call, was missing money, and still caused me so much grief that even when he was sober (or "sober?" -- I don't know anymore) I was a disaster because of the anxiety.
Are you willing to be in a relationship with someone who regularly disappears, doesn't come home when he is supposed to, and who always has some reasonable explanation why he can go off the map and not call or show his face to let you know plans changed, and imply that you're the unreasonable one for worrying?