Agreed, the pain and anguish is terrible. H selected you because there is something about you that he needed.
When H chooses OW, he either looks for someone who is the opposite of you, or someone who is very similar to you. If he chooses very similar, he's probably going to run into the same issues. If he chooses opposite, that's going to feel like a relief and a wonderful change in the short term, but it's doomed for failure because that's not what he needs longer term. Whatever it was about you that he needed and OM does not have, he will miss, and will eventually recognize that he needs to replace it, either by getting you back, or by finding someone like you. If she is very different from you, that is good news. He may have thought he wanted that, but he'll figure out it doesn't work for him.
Usually the things we love are the flipsides of the things we hate. It's a "ying yang" of relationships. We love people who are affectionate, but hate people who are clingy, which are often characteristics of the same behavior. We love people who engage with us, but can be bothered by people who depend on us. Once again, two sides of the same behavior. We like people who are funny, but don't like people who are insensitive. We like people who are confident, but we want to feel wanted, etc. etc. etc.
The complaints that H has about you are probably the other side of the things about you that he wants and needs. Your challenge is to maximize the Ying and minimize the Yang as it were. Your personality is your personality, but you can manage those traits to your advantage. Figure out what your good/bad flipsides are and make sure H sees the good side of it when you're in contact with him.
In terms of figuring out how this is going to work going forward, no rush. Tell H you're not ready to have those discussions yet. If he won't leave it open-ended, pick some number of weeks and agree to do it then. Do not feel any need to help him figure anything out. Don't propose any solutions, just accept or reject what he puts forth. You don't need to be his friend or his helper right now.
In terms of what OW said, I'd ignore that. There's nothing special about their relationship. If you look at Pat Love's website and download the resources about an "Office Spouse", all EA's tend to begin with people working together on some project and bonding over the experience, and they could just be a couple accountants. She does not have the inside track, you are the mother of his children, you have more shared history, you are the incumbent, and the best wife he could have.
In terms of how you handled his phone call, bravo! That was first class DB'ing!
Accuray
Married 18, Together 20, Now Divorced M: 48, W: 50, D: 18, S: 16, D: 12 Bomb Dropped (EA, D): 7/13/11 Start Reconcile: 8/15/11 Bomb Dropped (EA, D): 5/1/2014 (Divorced) In a New Relationship: 3/2015
