Yes I believe in the theory. I mean think about it, the space that our universe is expanding in to could be infinite. The chance that there was so other anomaly that resulted in the creation of another universe is highly likely. On top of that there is also the possibility of a higher plain of existence such as 4D, 5D, 6D, it goes on and on. Hell even 2D. Now all of those would have there own set of theoretical multiverses. I could even go to there being other universes that are on another plain of existence that are like us and are 3D. In the end you can look at this question for so many different angles. But yes I do believe in a multiverse.