
It sounds like you're doing a great job of educating yourself and validating his feelings. When you push back and say that you both need time to cool down in order to communicate effectively, how does he respond?
As for answering the calls, that depends. It sounds like you're not sure what you're going to get when you answer the phone. You should be able to protect yourself against unhealthy behavior, but it's also good to have lines of communication open if they can be constructive. Not answering might upset him more if he feels abandoned. You might try answering and seeing if it goes well. If he's nasty and you need to hang up, tell him you need to take a break for a specific period of time, and ask him if he'd like you to call him back. The important things are to periodically open up communications, protect yourself, and be predictable to him. What do you think?
RC