A, Your h thinks he wants freedom, freedom from the mundane, responsibilities, you, family, house, bill, etc. But, what he's not seeing right now is that no matter where he goes or what he does, he's going to have all of these things in his face each and every day. Yes, you and the children may not be there in the flesh, but in his mind, all of you are still there. As for the responsibilities, they will be there too. What's going on is "he can't let go". There are a number of them floating round like that. Some even get remarried and still are attached to their former spouse in some way. His calling up and chatting about mundane things is a prime example. Be courteous, but cut the calls short and get off the phone. He needs to understand that you are busy, you have the children to look after and one other thing--you have a life that you need to live.
Keep moving forward and do not look back. Time is on your side and the man upstairs will guide you.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.