I know exactly how you feel! I was thinking and doing the same things many years ago. It's not easy, but you have to keep that finger off the iPhone!
I'll try to help you w/some of your questions. In some ways, yes, he's enjoying himself, but the euphoria of being on his own will eventually get boring and old.
There is the possibility that if there is OW in the picture she may know something about you, but not all of it. They tend to share some stuff w/them as to why they feel so unhappy and want out of the marriage. They do not share everything or the OW would be questioning why he left you in the first place.
There is the possibility that he's saying some of the same things to her that he did to you in the beginning, but generally, the discussions are about his unhappiness and they tend to be chameleons whereby they take up the interests of the ow. For example, if the ow likes a certain music, they'll start to listen to it, etc. They reinvent themselves to fit their situation at that time. So, most likely they will be talking about the things that they want to do together. However, they have been known to take the ow/op to the same vacation spots, cafes, etc., as they did w/you. Why? Because they are familiar to them and yes, they enjoyed themselves while there w/you.
There is also the possibility that he is writing letters/cards to her. Some even write poetry or music for the "sudden" loves.
As for leaving much of his stuff behind is not what you think. In some instances, it is a link back to you and your home and they use the excuse of coming there to get something to do a temp check on you and see what you are up to. In another case, it could be that he's reinvented himself and he doesn't want to be reminded of the past w/the clothes, so he's purchased new "hip" clothes that fit his current lifestyle. As for having to face you again, he could very well ask that you pack stuff up and put it somewhere easy to get to and come when you aren't there.
No one can answer the question about receiving D papers out of the blue because each situation is different.
He thinks about you often, especially when he's alone at night. How could he not? You've spent a lot of time together. He works extra hard not to think about you and the distractions during the day help him w/that.
About your temptation to contact him...don't! Leave him be. He will contact you when he's ready to do so. When will that be? No one can answer that question for you...but he will. Put a rubber band around your wrist and snap it hard when the temptations arises whereby you want to text him.
All of your questions are valid questions and we all ask ourselves these questions in the beginning. Your mind is working overtime and your anxiety is up. Have faith in yourself and the man upstairs. Find things to keep your focus elsewhere and know that the man upstairs is working on him. One last thing...breathe!
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.
