What do you think would’ve happened if Catherine of Aragon had lived longer? As if to see (not literally) Anne’s execution? Do you think she would have been happy? Do you think she would’ve expected Henry to return to her? Do you think things would’ve turned out differenly with his other wives, for example, would Jane seymour have become his next wife?
I actually don't think that Anne would have been executed if Catherine had still been alive as I think that Henry would have been forced into admitting that his second marriage was a mistake and forced into returning to Catherine. I think Anne was actually safe while Catherine was still alive, although she saw Catherine as a threat and a hindrance.