Bluefox
It is a combination of things. The unknown is one, leaving something familiar so try and turn it into an adventure
The house itself, it needs to release you and you need to say goodbye. It will happen, start packing now, it takes a lot of time and effort and bit by bit, those bonds will break. You might not realise it but that process has already started
Give your husband one small definite job at a time, packing ornaments would be good, get him to seal the box and label it and store it in a definite room. Keep him busy but only one task at a time, so it gets completed fairly quickly
Also plan ahead, task him with making scale drawings of the rooms in the new home and then you can both work out what is going where. Thinking ahead like this will help him to focus ahead and not behind