perhaps try putting it in the dryer- for just a few minutes---to warm it- then maybe you can carefully pull it apart. i'd be afraid to loosen it with an iron-but a dryer might work...keep an eye on it though- try a few minutes- if it seems to work you can put it back in for a few more minutes---
then when you are going to store it- make sure to fold it so the fusable side is not against itself---you could put parchment paper over it- then fold it. good luck (