hi cytagirl-
i would be glad that he is willing to go and also, that you got your key back. i know it's hard but try not to take it personally....it is about the drink.
when you get in the way of the drink, an alcoholic will frequently get themselves another enabler. don't take that personally either. it is about the drink.
if you can, have a friend in the house when he comes to get his things. or better yet, agree to a drop off point which isn't your home. leaving is a dangerous time and he might be surprised that you're going thru with it.
i would also change the locks and change your phone number. i know that sounds dramatic, but it could save you a lot of heartache in the future.
to answer your question about how they can move on so quickly, it is because alcholics will protect their right to drink and eliminate people who get in the way of that. also, they do not have to deal with their feelings, as they can just have another drink and numb themselves that way.
naive