My heart goes out to both of you....I can relate, my H did have EA twice, but 9 yrs apart and with 2 different women. Zilla, you are in my prayers, I sort of understand what you are feeling here....and while I can say I don't understand your H's actions, I think you can be proud of him in at least this way - here is a man who has the courage to come here with you, admit his wrongs, and do his best to make it right!
Now, can I ask your H - please keep posting what your thoughts are during this - it would help so much those of us who are on this side, to see/hear what our spouse may be thinking or feeling. My H has refused to speak to me about his feelings or thoughts in losing our family....but I still have enough faith in him as a good man to know he is feeling pain and confusion, even if he isn't expressing it. So your H's perspective here could be priceless to some of us.
Now having said that, can I just offer you whatever support I can? I don't know what that is, but my heart just hurts for what I know you are feeling right now. I think you and I may be very similar - my H also said I was controlling, and my defense is I only controlled when he didn't and it needed done...then it became a habit! I was not there for him in the ways he recognized, and he turned to someone else to feel wonderful. My H did tell me after the first EA that it was an escape for him, he always knew it wasn't real life, and that in real life he loved me, but he was needing female attention that I wasn't giving at that time (3 babies in 5 years), and instead of being direct and letting me know, he went out to get his ego stroked somewhere else. Does it make it better? Well, no, but knowing it was his ego and not his love was the only thing that meant I was willing to forgive.
It doesn't sound like this woman is really going to be a threat to your marriage. She has moved, and your H says he is more annoyed by her calls....but she is playing the helpless female and he feels obligated in a way to continue the contact (To H - STOP!) You can get her out of the picture, work on your marriage, and still be together - but you are right it will be harder this time.
We seem to find out we can always trust our gut, don't we? I knew the second EA was coming almost from the day the OW started making a play for my H. I saw the change in her behavior toward me, and toward him. He wouldn't listen to me, and fell right into it, even with the EA in our past - he wouldn't trust my instincts that this was a woman to stay away from. Sometimes women can sense these things much better than men.
Good luck to the both of you! We are all rooting for you here, and I, for one, don't consider this a failure....it may be a setback, but NOT a failure!