I'm not going to wear my engagement ring when I go out with my friends at night
Are you planning to appear single by removing your wedding ring?
I want to be free so I don't want to wear it
You are not being honest with your fiance by hiding the fact that you are engaged. If you want to be single then you should break off the engagement or he will break it off with you when he finds out about your behavior.
I want to be single, I don't want to be with him anymore.
Then you will have a long conversation with your fiancee. Why say yes when you weren't sure of the answer? Stop playing around and be responsible.