I'm sorry to say that I didn't like this one at all.
Ultimately, I believe that Future Perfect failed to hold together on a thematic level. The main character's many permutations - she was clearly altering every possible variable in her life, not just the small ones - showed that there was nothing essentially "her" about herself. I know it's true that I could be almost anyone if the circumstances of my life were changed, but really? Award winning physicist, crack whore, normal nice guy, serial rapist/murderer... these people are so incredibly varied that the changes she was making in each alternate universe were not small. Why were they even a woman and a man in each world? Why did he always have those same striking green eyes? Why weren't they lizard people? Why is the side of my head sticky? Anyway, the point I'm making is what was she hoping to find in these worlds? Given that she was willing to sacrifice everything about herself for this all-consuming "love," why did she think she would still be someone capable of appreciating it if she ever found it?
In other words, you can have determinism, a world in which she is who she is on some level, regardless of her circumstances, and so is he, or you can have free will. You can't have both.
My second beef with the story is more personal than thematic. I though that the character's interpretation of love was incredibly adolescent. I'm lucky enough to be in love with my fabulous wife, and I am confident in saying that love is not a moment of connection in a crowded party. Love is a choice I make day after day. I don't have a problem with a character who has a painfully adolescent idea of love, but if you're going to write a supposedly mature woman - a grad student - with such a teenage idea of love, you've got to tell me why. What's her damage? Why is she a grown woman who still loves like a twelve year old?
This brings me to my final problem with the story: ego dilution. The story spent so much of its time in alternate realities that we never got to know the main character for herself. That potentiated with her weird idea of love to create a deadly cocktail of disbelief that ultimately prevented me from enjoying the story.
Or maybe I'm just in a bad mood. I seem to dislike a lot of stories right now.
Anyway, I felt like there was a good story buried in here, somewhere, but the premise needed to be thought out a little more and the structure replaced with one that didn't leave me wondering quite so much as to the main character's motivation.
So, yeah. Better luck next time.