Want to change email on Apple ID

In setting up my new iphone 11, I put in my email address of ***@gmail.com and it wouldn't accept it. It said that was already taken. But it is the only active email address I have. So, I set it up with my wife's, ***@gmail.com. But now I need to change it to my email address and it still won't let me. I want emails to come to me and not my wife. It's too confusing the way it is. How can I correct it?

[Edited by Moderator]