Please let me change your mind. My wife has loved Lord of the Rings since she was a child. Whenever we talk about it, it's like bringing up distant memories of an old loved one. Her mind goes to another place: this place. I know this world already lives inside her. I would like very much to take her to this world you created and walk through it with her as she sees it for the first time as if she's there. It would mean a lot to be able to do that without any distractions, such as other players jumping through with out-of-character skins. Playing at 2 in the morning isn't an option for her due to sleep issues.
I understand this is an original work you made, and you're concerned about other people stealing it. I'm not an attorney, but I've dealt with copyright issues in the past, and I know any attorney would tell you that you would be protected by copyright law. Copyright law is very strict these days. Any original work you create is protected. Minecraft is just a tool of creation. Vanilla textures belong to Microsoft, but all other work, such as the arrangement of blocks, new textures, and all the intellectual and manual labor that went into it is protected by copyright law. The only requirement is to prove you are the original author, which is very easy in your case, as you have a website, forum, YouTube videos, and backup logs of the world that would predate anyone else's. I'm sure you'd be protected.
If anyone were to infringe on your work, enforcing the copyright is as easy as sending a DMCA Takedown notice to the host. There are instructions on how to do that on many sites, or you could pay $10/mo to have
DMCA Protection & Takedown Services do it. If the host doesn't take it down right away, you would make a lot of money from them in court:
Copyright Infringement: How Are Damage Amounts Determined?
If you choose not to release it, people like my wife and I won't be able to enjoy it privately. If you do release it, your rights as a creator are still protected, except you allow people like us to experience your creation in its purest form. It's up to you what you want to do with it, but I hope this helps you change your mind.