Oh, my goodness...the old paper bag moving techniques. He'll probably take his underwear and socks and think that because he can only carry a little bit over he then can continue coming to your home and yes, slowly but surely sneak a few things out that you won't miss until later. I would suggest that you walk around and take note of your home. The items may not necessarily be expensive, but he will definitely take some things that you will miss when you go to use them again.
I'm sure he'll be coming back over and will be madder than an old wet hen that he can't get in. That's when you need to set a time for him to pick up the rest of his belongings, while you or someone is there.
Sure sounds a lot like my xh and Sting's h (many years ago).
Good luck!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.