I'm glad you finally heard from him...but this phone thing really does need to be addressed.
Here is the list of things the cheating spouse needs to do. It's listed in many, many books...and most therapists will back this up as well.
In order for your marriage to successfully survive these are some things that your spouse must do:
He must be totally honest with you about everything He must answer every question that you ask truthfully and fully. He must do everything in his power to prove to you that you are the one that he wants to be with. He must prove his love to you...he must be patient, gentle, compassionate and understanding. He must feel your pain. He must fully understand the devastation that he caused you. He must accept full responsibility for his actions. He must stop all contact with OP and not try to protect them. He must reassure you that it is OK to ask questions. He must reassure you that you will not drive him away by doing the things that are necessary to heal. He must recognize when your struggling or experiencing a trigger and comfort you. He must be able to tell you how sorry he is and show you. He must re-enforce to you, that you are not responsible. He must put his own feelings of guilt and shame aside and help you heal first. He must reconnect emotionally, mentally, and physically with you and stay connected. He must work on rebuilding trust. No secrets. No privacy. He must be willing to seek counseling. He must learn what is and is not acceptable when communicating with the opposite sex...he must establish boundaries and not cross them.
Obviously I hilighted those things in red that this phone issue directly ties to. I hope he gets it.
Ya know...if you don't have the book "After the Affair" you might pick that up. It outlines all of this stuff too...ask him to read it. It actually is a good book, I found it quite helpful for my own healing...but it gives what needs to be done after the affair for the betrayed spouse to heal....both work for the betrayed spouse to do, and what the wandering spouse needs to do and what they should expect of their betrayed partner. Do you think at a minimum he'd be willing to read it?