No one created Him. Our universe, and everything in it, had a beginning. God is Spirit. I don't know exactly what that is, but it is something greater than and apart from our physical universe. So He has no beginning. I realize that it's difficult to wrap your mind around such a concept, but the alternative is to believe that the universe created itself. That's what you believe, isn't it? That it just exists for no reason at all? How is that any more logical than believing in a Creator?
Because there are so many more possibilities you haven't even considered. You are correct it is hard to wrap your brain around this, but there was time and space before our universe was created. Think of us as one bubble in a lava lamp

Your universe is just one of a google of universes in an infinite cosmos. You seem to be putting god and/or the cosmos in a box my friend. God isn't eternal and it isn't GOD that has no beginning and no end. The cosmos do.
You can not disagree because even if there is a god and even if he did live forever, he had to live somewhere. And if there is a god, which there probably is not, but if there is, he is a lot older than 13.5 billion years old, am I right?
What created that one little bubble in the bottom right of that lava lamp? To the things that live in that bubble, they can not see the other bubbles, just like you can not see other universes. Not yet anyways.