I'm no physicist so I wouldn't claim to understand the multiverse theory, but I think such trivial interpretations are populace's trash. I find really hard to believe that, just because I can imagine/conceive it, there is a world with an english flying boy called Peter Pan who remains one day old... and whose mother has tentacles for nipples and fangs that reach her anus like those of the in-world green photosynthetic elephants (see what I mean?)... In any case, even if such weird and inaccesible universes were to exist, how could we assert to have any knowledge and love for it, if we can't gather objective knowledge (and love) even from this universe of our own? Once again, the entities living there would be some alterities and not be the things we love, it's ridiculous.
Mai waifu exists, say, as God, numbers, holotypes or abelian groups: as metaphysical concepts that we grasp and use through some semiotic process of representation (narrative, plastic arts, music, biology, maths,...). She is overtly fictional. a frontal lie, and that makes my love honest within this existence haunted by the scam of language et al. signs.