Fiance's Friend

Taylor
So my fiance has told me that I'm not allowed to talk to his friend. We'll call him Joe. Any other friend is fine, but when it comes to Joe I am absolutely not allowed to talk to him, be friends with him on facebook, etc. He says it's because he doesn't trust him. My argument is that if you really don't trust this friend to that extent....then why the f*** are you friends with him still? His argument? Because he want to be. Um.....what? Ladies, I could use some advice on this one.