I am sorry you are going through so much. But it also seems clear that John has neither the bandwidth nor desire to be in this relationship with you. Of course, your children and grandchildren will always come first. If John can’t understand this or doesn’t have the skills do it, it is time to grieve the relationship so it will free you up to move on.
John has told you in his own way that he isn’t able to make this journey with you. Accepting that this is the way it is will allow you to unhook from him and devote your energy to something — or someone more worthwhile.
I’d highly recommend some brief individual therapy to help you grieve and move on. The Find Help tab at the top of the page will help you find someone in your area.
Wishing you patience and peace,
Proof Positive Blog @ PsychCentral