Actually, along with many women from that era, she didn't believe that divorce should be allowed to happen, whatever the reason, nothing to do with the family.
Then again she came from the days that also allowed hanging and whipping school children. She also believed, IMO, that a woman was faithful to her husband, no matter how many lady friends he may have had.
Well, it's been said by some of the royal commentators that Charles and Camilla wouldn't be getting married during the Queen Mother's lifetime because the Queen Mother felt so strongly about divorce and remarriage. On the other hand, it's a shame that at some point during the Queen Mother's lifetime, the Queen didn't cut the apron strings and tell Mummy that times had moved on even if she hadn't. The sort of morality that was perfectly happy for Edward VIII, when Prince of Wales, to have a married mistress who'd already been divorced and remarried (Thelma Furness) but flat-out rejected the notion of his having a wife who'd already been divorced and remarried is a very selective one. It's a shame Prince Charles was held hostage to that double standard for so long.