It's definitely a plausible idea, but that means it wouldn't help you even if it could. If you really believe in it, you should try your hardest to disprove it using anything from science to personal experiences.

Scientifically, you got a lot going for you. Most physicists nowadays believe in multiple universes, or rather, they're forced to believe in them so that their field becomes valid(String theory, Quantum theory, Graviton particles, etc).

It's also generally believed that it's human observation that prevents particles from super positioning.

However, there's a difference between observation and thinking. Thinking does nothing to change the particles in any way. In the double-slit experiment, you will always be able to observe the results of a photon super positioning, irregardless of what you're wishing/not wishing the result to be.

Also, don't put too much weight on the Schrödinger's Cat paradox. It's purpose was to show that we still don't get something about quantum physics, not that the cat is both dead and alive before we open the box.