Have you ever had a prenup and then had to invoke it as part of a divorce? How did it go? Was it useful or was it invalidated for some reason? Any advice?

Please only respond if you ACTUALLY had a prenup, or know someone who had a prenup and then got divorced. Everyone seems to have opinions about prenups, but I think it would be most helpful to hear from people who had a prenup and needed to invoke it in a divorce.