Universe to some people means "Everything that exists". So if it turns out that our universe is a part of a larger multi-verse, to those people "universe" would then mean "potentially infinite multiverse"
Having said that, how do you know the universe is not infinite?
The universe basically means the observable universe. That is by definition not infinite. Everything that exists is not the same as the universe, as the latter is a physical thing. Thoughts exist, but I wouldn't consider them 'part of the universe'. People may understand all kinds of things as 'the universe', but that's not very helpful in a discussion, unless to clarify what different people understand to mean 'the universe'...
I said its possible and I was asked for a link by somebody else which I provided. That really is the issue.
A lot of things are possible, theoretically.. That doesn't make them probable though. It's possible that God exists, and that I am firmly convinced of it as well. That's not something quantifiable or testable though, God. So while it's entirely possible, it's of no use in science.
Too bad becouse I am fairly sure this universe is part of an infinite multiverse.
Well, that would be a personal opinion then. It's possible, but there's no indication that it's correct. So that would qualify as pure speculation - even if it's done by cosmologists. Maybe at some point in the future it will be possible to test this theory; and then it may either be or not be scientific theory.