Don't beat yourself up. Rip is right. You are a good and decent man who is trying to do the right thing. You are seeing a lot of progress, she is contacting you and talking to you in a positive way, those are steps forward.
However, she is still involved with her OM, therefore you can't be a friend or sounding board. Personally I would ignore those texts and/or emails. Let her miss the capabale and caring Kramer that she depended upon and loved for 17 years, that's a long time.
Do you want to be a friend or husband? She is divorcing you and has made it clear she is with the OM and continues to be his friend/lover.
Stand firm and continue to DB.
That is my .02 cents - choose to ignore if you want to.
