'I am the one whose life I live' has no alternative

The fact is it is my life I live. There may be theories about alternative universes or parallel spaces from quantum states and the likes but the fact remains that what happens in this moment in time is after the causal physical fact of what happened in the previous. An alternative universe/space has the effect from what happened previously in that space and may and may not have influence on this depending on how much I include aspects from that alternative space in the present moment by which something becomes possible in this and therefore the next moment has the effect of it. Nevertheless, that alternative space has me, even if as an alter ego or whatsoever, but it is me, not somebody else, even if that me is a theatrical version of me whose affects contribute by refraction within the spectrum that is my-space and gives me range to derive and arrive from. It is moot point to think somebody else could have done better or worse because the fact is I am here in this physical space doing what I am doing as a consequence of laws of physics in this space because of which I factually am doing what I am doing in this lifetime.