I think it is a very mature decision for you to make and it's good to know what your boundaries are. It's best to tell him open and honest you are waiting, bf tells me all the time he isn't a mind reader. Most guys perfer to be told straight up and honestly, if this guy really cares about you he will respect your decision and wait. I know a couple I am friends with and the girl has made the same choice, and her bf respects that, they have been together 5 years and are engaged now. I hope this works for you and luck on talking to the guy.