I don't want to have a wedding.
Is there a reason why the wedding would be a bad idea?
I think a wedding will be a waste of money
If you don't want to get married you shouldn't have to. You can change your mind later on but it's okay to not want to.
My wife knows I don't want a wedding.
Then there should be no issue. you do not have to get married if you do not want to. Marriage is just a piece of paper after all.