I’d say it’s analogous to quantum mechanics- 50/50. It maybe does exist until we observe it, which is why it is an elusive concept to grasp. It’s in the state of existence until we look for it, at which point it no longer exists. As a physics major, I learned to accept that some things are just beyond our limit of perception as human beings. I think if we could somehow detach our consciousness from our mind and be just that - a consciousness without our body (which is bound to this reality), we could see through the proper lens to answer your question. However, we are limited to the physics of our dimension. As Einstein said about quantum entanglement - “spooky action at a distance.” I think the same can be said for multiverses. It’s simply that - a spooky concept that resides a great distance from our reality. Maybe beyond this life, but in this one - its a philosophical theory. I sometimes think this reality would crumble if we could answer such things. I don’t think our minds could handle such a truth.