You H sounds so so sooooo much like my H...the trigger for my H was 2 years BEFORE the bomb!...he was laid off from work and started a new career...one that didn't really go so well...and started the downward spiral that I didn't understand at the time...
My H didn't care...didn't call...didn't return calls to his son (the girls wouldn't speak to him after he left)...said pretty much the same things your does when he was still home...he would leave for work and not come in until 2 am...sometimes stinking drunk...when I would tell him I was worried about and a call would have been nice he would tell me "I have been on this earth 46 years and nothing has happened. If something happens you will know so there is no point in worring!"
Don't let him know your worried...you really MUST stop questioning...he is feeling driven by an internal force that is stronger then anything right now...even stronger then love...my H told me that my love was not enough...that it takes more then love to stay together...that isn't what I believe...and now I know I was right because it was my love that brought him home...
When my H left there was no warning...he kissed me good bye at my nieces wedding...said he would see me for dinner and that was it...I realized that he was probably drinking in his office and when he wouldn't answer the door I left him a note saying I had the car and he could call when he needed a ride home...he called at 3 am...wouldn't talk to me on the phone but said to come get him...on the way home he said he was leaving...that he just needed to get his shaving kit???
He literally left his life behind when he walked out the door...I had never seen such a cold man...didn't say good bye to his children...didn't take his prized guitar...his family momentos...NOTHING but his shaving kit....the debt he ran up starting over was incredible...I soon realized that between the OW and THINGS he was trying to find happiness...he had blamed me for all his unhappiness...said he hadn't been happy for "10 years" and like your Treese...our son was 9 which meant that during the pregnancy he was not happy???...I was as bewildered as you...as deeply hurt as you...sometimes I wished that he had died and not left me...at least I would have felt loved and loveable...now I was humiliated and unloved by him...I was devistated to say the least...I have never felt such pain...
BUT...when I found this place...realized that I had a part in all of this...that my focus was now on me and the kids...I kicked into gear...I even got a job that really made me thankful for the life I had...as miserable as I thought it was I had to really focus on the blessings that I had in my life...that is what you all have to do...there is nothing you can do to MAKE your H come home...or realize what he is doing is wrong...his feelings are VERY real to him...he is totally convinced he is doing the right thing...no matter how wrong it really is...this is where you have to really pity him...he doesn't even know how messed up he is and when he realizes it that will be a big blow to him...and he just might NEED a friend...until then you can't be anything to him...you just have to BE...