I think you might be misunderstanding or overcomplicating, or I might be misunderstanding you.

Basically, if you're making a decision between A and B, the outcome of A will always be the same, and the outcome of B will always be the same, but the outcomes of A and B are not the same, if that makes since. You're basically choosing outcomes that you don't know. Apply this to every decision or occurance ever to take place. You get an infinitely large number of possibilities, and consequently an infinitely large number of alternate realities.