According to your thinking, it would seem to me that every time you make a discussion no matter how small and act on it you pick a different universe. As an example, there is the universe where you scratched your nose and the one where you created your nose two seconds later. And such small differences can be highly significant. Such a small movement would alter the movement of the entire body slightly. For example, if this movement was done during sex and made a slight alteration in the location of the sperms in the testis when ejaculation occurred, a different sperm would end up winning the race to the egg and a completely different baby would be born. It would be in effect a fraternal twin to the one who would have been born.