Nic - he is comfortable where he is at... that is where he will stay.
Utlimately - its time to move on. I'm not saying you have to put forth the D... but you need to move on.
How many times must he call a day? a week? You decide. When he calls give the phone to your Daughter. Stop being available for all those calls. He has a headache??? Boohoo... he is a physician he should know how to heal thy self. He wants to whine... and you let him.
You've discussed items for Christmas... its done. No more to discuss.
You keep answering the phone or wallowing when you don't that he may want to have the talk about coming back. Here's the kicker. Let's say he does want to come back, you NOT taking that call won't stop it... he will just be more determined to get through to you.
Nic, I've said it over and over again. He knows you are just sitting there waiting for him to decide if he wants to come back. He is not the least bit worried about losing you.
I don't have a crystal ball. I know how hard and how painful of a time this is. Your hopes of a united family - how seriously you took your marriage vows, etc. I am not belittling any of that torture. But you have to stop living your life on when or maybe your H will give it one last shot. Trust me - they won't feel the panic of loss unless they truly have.