I can't really come to terms with the Multiverse theory, because it means that with infinite universes, there are infinite variables, and so that in another universe a certain law of physics may prohibit the existence of other universes, creating a somewhat paradoxical situation.
The only reason that I know that the Multiverse theory comes into play, is because of a desire for a solution to the time travel paradoxes.
Since going on a spaceship, traveling at several thousands km/h we find ourselves to have traveled forward in time slightly. But that doesn't mean we can encounter a future version of ourselves whatsoever.
The same would apply in traveling back in time. It makes no difference if it's a fraction of a second or 10 years, does it not? And if we are able to slow our own motion relative to the absolute movement of all matter in the universe, for we do have mass, meaning we are all moving when we seem to be standing still in space. That slowing ourselves down, relative to the absolute movement of all matter, then perhaps we can travel back in time, but for the same situation as in traveling forwards for 1 second or 1,000 years, we don't encounter ourselves, so that the grandfather paradox and whatever else does not apply. In that, perhaps the different times are not connected, for if we killed our grandfather right now, or 10 years ago, we exist perfectly like anyone else. If someone was to observe us, while we were traveling at that "negative" velocity, we would observe our absolute motion, whichever direction it may be, but if we could see to infinite, we would see that they are still there.
But perhaps it's a different approach than that, an argument to rebuff that, is that time will actually speed up for us, in that we still travel into the future with everyone else, but to go an hour, it may feel or take us 10 years.
In that, I don't think that we'll ever come into the scenario where we would be able to apply the multiverse theory, but who knows.
