he is too ashamed to talk to me on the phone. We communicate by e-mail only-which is amazing in itself after the pain I suffered and his level of guilt.
Does this mean that you would like to talk to him on the phone but he isn't feeling up to it? When you say your email communication is amazing, does that mean that you consider it amazing that you're still willing to talk to him, or amazing that he can pull himself out of his own guilt enough to send you an email?
Another part of the "bad act" is avoiding exactly this type of confrontation: I am too terrible to talk to you, I am not good enough to be around you, the bad things I have done eat at me with so much guilt that it paralyzes me to think about them, and therefore, I am unable to think about them, or talk to you, or give you any answers or make an effort to change.
I think this is a way of "protecting" the act-- so that even if you do get caught and tell, you'll still have your old bad life to fall back on when change gets too hard. Remember, AB, if his whole life is built on this "bad" image, then however much he may want to change things, changing this means abandoning the only identity he has--a scary prospect even if the identity is crap.
As long as you let his guilt and bad feelings dominate your interactions with him, he's not going to get serious about rebuilding a relationship with you as a part of the new act. Every time he reads your email, he's going to think somewhere in the back of his mind, "what a jerk I am, if I weren't such a jerk she'd be telling me this on the phone."
Let him know (again and again if needed) that you still love him, you want to be a part of his recovery, you don't think he's not worth a phone call, and then step back and let him live up to your expectations. When he's ready to, he will. HE'S the one who's gone so far down the road. HE's the one who needs to come back. Not you. If you want him to come back to you, you need to let him do the walking. Otherwise you'll just end up meeting him in the bad place where he is right now.