outonalimb, it never rains but it pours...
this is just way too much at one time - your AH and now having a son who's metamorphosed into a teenager.
My youngest (a son) is now almost 30, and has 8 month old twins, but I remember it well - - we had 5 kids altogether, and they all turned into aliens for a while. The good news is that they do become human again. My 2 kids have been the most wonderful support.
There are 2 things I can say. First, don't try to be your son's friend. What he needs is a parent. This is a major separation age, a lot like the 2 year old version. Kids have to test the limits to see who they are and who they aren't. The secret that I finally realized was that they WANT the limits because there is security in that. They can test their independence as much as they want, but they trust that you won't really let them make major mistakes.
Second, I can bequeath you the disciplinary sentence that I FINALLY developed, after everything else failed:
"Don't do anything that you couldn't do without me standing right in front of you watching everything you do"....
Take care, we're all here with you and for you!
ShootingStar1