OP I’m sorry to read that you lost your mother young.
But I must say that I don’t agree that W and C would be “letting each other down” if they divorced as amicably as possible and with due care for the children. They could both be enriched by a parting of the ways if they’ve been miserable and at odds. They are supposed to be the future king and queen but they’re human beings first and they must do what’s right for their relationship, whilst ensuring the children are ok.
Charles and Diana had become friends just before her car crash, Anne remained friends with Mark as did Camilla with her ex. It’s possible that whilst a divorce might be a constitutional headache (or would it?) it wouldn’t be a disaster.
That’s assuming the rumours of unhappiness are true. I’ve no idea needless to say.