A common thing I see brought up in discussions about the multiverse is that god would have to exist because in an infinite number of possible universes that option would have played out. This is incorrect, and a common misconception regarding infinity, probability, and restrictions. It has a lot to do with our hesitance to even accept infinities as possible to begin with.
The reason we humans recoil at the concept of infinities has much to do with our very limited brains, conditioned to perceive reality in finite concise terms. Knowing it is our limitation, not one of any absolute sense, infinities, as repugnant as they seem, are nonetheless possible.
We need only remember that some natural concept of infinity, like an infinite multiverse, is still superior to the alternative, an infinite god, as it at least does not invoke magic as an explanation.
The other thing about infinite universes is that it does not necessarily lead to the slippery slope of ANYTHING being possible. There may well be restrictions on what configurations can exist, even when an infinite number of universes are posited to exist.
Think about it this way. If I had an infinite number of blue and red marbles, there is still no possibility that a green marble exists. One can have conditional restraints on an infinite set. And using the marble analogy, just because an infinite number of them exists does not make the existence of a magical marble possible.
There may indeed be an infinite number of universes, of which ours is the one (or one of the ones) where life happened. But there may be a limit on how dimensions can fold and unfold, how time can operate, and how energy can be used in any universe, restricting the possible configurations of these infinite universes. Thus you would get copies of universes, with nearly or exactly the same properties. There could even be millions or billions of possible configurations, but still be a finite number of possibilities none the less. Thus you could have an infinite number of universes with a finite number of configurations possible. This would be like having a hundred different colored gum balls possible, while having an infinite number of gum balls of those colors. The number of colors would not be infinite. Just the number of gum balls with those colors. Likewise, there may well be an infinite number of universes, but the number of possible configurations might be finite.
Anything we can conceive would not then be automatically possible just because an infinite number of universes might exist. Only possibilities that lie within the restrictions that apply to possible universe configurations could exist. And there is no guarantee that all configurations have been assembled in the first place. There may well be some configurations that are possible that have not occurred yet, especially if the configuration of any new universe is determined by a random event.
Of course, the knowledge of what these restrictions are might be forever beyond our ability to ascertain, given that our tests and observations seem to only be limited to what is inside our universe. We then only know of one possible configuration that is possible... our universe. We would have no way of forming a data set of possible configurations of other universes as we would have no way of determining what rules govern universe configurations.
Let me find an asprin. My head hurts.