Ashamed, you should change your name and not be ashamed, that's for sure! You've got a good head on your shoulders. Thanks for coming out of lurking mode! May I ask how long you've been separated? The reason I ask is that usually sooner or later they will come out of the "best behavior" when they see they're still not getting their way and become monsters again to you. The allowing him back in for a bit for the car thing might have given him hope that you will take him back and he kind of was trying to force his way back. If you firmly re-set your boundaries with him, it will be interesting to see if he remains on his "best behavior" or not. What do you expect him to be like and how long do you think this best behavior will last?
ETA: sorry, I went back and saw you've been separated for about a year.