I have read your sitch, and I so know what you are feeling. I was there. Am still there in some ways. My H was my whole life. I still feel like I am "just going through the motions" almost daily. But it does get better.
Peacetoday said it very well. You need to use this time to work on you and what makes you happy (although it may feel that nothing can make you happy at this point). It's about saving you not the M....... but saving yourself is the best chance you have at reconciliation down the road.
The best advice I can give is to remember to be kind to yourself!! There are really no "right" or "wrong" answers. This is a journey that we each have to take and what works for one may not work for another. You will learn much in your own sitch by trial and error. You have to become your own best friend!
We can all tell from reading what you have written that you are a warm, loving, woman with good values and you do indeed "deserve better". Your H is concentrating blame on you because that makes it easier for him not to look in the mirror. Try not to listen in to his rhetoric. Understand that it comes from his own pain (at himself I think possibly more than you although he likely doesn't recognise that!).
One book that really helped me that I suspect may help you is "Facing Love Addiction" by Pia Mellody. It really opened my eyes and maybe it will for you to.
And one last thing, don't let your H mess with you about "screwing him over" in the D. I'm betting that is a just another tactic to make you feel guilty and to deflect blame. The truth is that WA state is a "no fault" state and "screwing over" one's spouse is not so easy.
Hang in there, sweetie!!
((((((HUGS))))))
TJ
Me45,H49 D24,S18 M26,T28 Bomb 3/19/08 Sep 6/23/08 EA/PA with Secretary 2007-8 3/2009 H moved in w/OW2 7/2009 Let him go w/Love. 8/2009 Legally Sep'd