(1) How exactly have you been played? You cheated on W prior to M, you were abusive, she left you and has been very clear about not wanting to reconcile.
(2) You are in no way in a good place to date.
(3) You wrote: "I overextended myself financially in doing this based on my "nice guy" m.o. and harbored resentment as a result when I wasn't treated the way I wanted in return. This was a catalyst for my drinking and handful of verbally abusive epsisodes that ultimately pushed her into the arms of OM and put the nail in the coffin of our M.
I think I finally "get it" now. I see why I behaved the way I did, and I know it will not happen again in the future."
Uh, no. Your behavior hasn't changed. How you describe things hasn't changed. Your lack of ownership hasn't changed. Your continuing to minimize your abuse hasn't changed. Alcoholics and abusers can ALWAYS point to a triggering incident. So what.
"I haven't seen her or my stepkids since Valentines day, so there's really not much of way for her to see any of my changes. The thing I still don't get is the discipline to abide by the DB principles because I keep screwing up. "
Precisely. There has been no real change on your part. PLEASE do not start dating.