He left our newborn baby in the car.....

So the other night at about 3am, I'm feeding our 5 week old baby in our bedroom.  My ADD husband finally comes upstairs to go to bed.  He comes in and has this "look" on his face...a look he gets when he's really guilty about something.  He admits to me that when he took our baby to the store to buy some ice cream that evening, he forgot/left her in the car.  He didn't tell me all evening.  When he told me, I was half asleep so at first it was hard to comprehend and I know I didn't react as strongly than I would have fully awake (maybe he knew that??).  It was, thank GOODNESS, a very short trip, maybe 5 minutes, into the store.  It was about 7pm when he went but quite hot outside.  He didn't realize what he did until he opened the door to get back into the car and he heard screaming.  It broke my heart when he told me how her eyes were so wide as she cried, like she knew something was wrong.  It took me a few minutes after him telling me, for it to sink in.  Then I started lightly crying as I looked at my baby I was feeding and thought about how this could have happened with a longer store trip and who knows what would happen to her, geez I'm crying again.  I was and am not angry with my husband, just very scared.  And a little heartbroken.  I know he feels completely awful.  Since he told me this, though, he seems to be keeping himself extra busy with random household jobs.  Perhaps distracting him from thinking about what he did....perhaps not giving him and I a chance to talk and risk me bringing it up again.  We really talked about it very little that first night as I was trying to put the baby back to sleep and didn't want to make much noise.  As for me, it's such a horrible and awful thing to do, leaving a child in a car, I feel as if I'm a bit numb to what he did.  Like I'm not letting myself really feel or react to this.  I'm not sure why.  Maybe a bit of disbelief?  Hard to comprehend that someone could do that to my tiny baby?  I really want to know more about how my husband feels about this and how he's reacted.  I don't know how to bring it up.  The main reason I want to bring it up with him is this: the night he told me, he mentioned how maybe he needs to go back on his meds so something like this doesn't happen again.  He desperately needs to go back on his meds (he quit about a month ago) but using this awful situation as a reason to do it....I don't know, feels strange.  Like I said, I think I'm just numb to all of this.  Heartbroken, but numb.  Is it awful to think, if he can do something like this, could he do something just as bad or worse?  I don't know.  Just a bit shocked.....I also feel like I can't tell a single person about this since it's so awful, so it feels good to at least write about it here.