Talkative man

So, my boyfriend and I have been dating for a while now and I've come to learn that I'm reserved and not the one to tell people things while he will say certain things to others and not have a problem. I'm not comfortable telling him certain telling others certain things that hebsndshould be the only one to know. Certain information that should be kept between us, he tells others and it annoys me. It is as if I'm in a relationship with him and the world. What am I to do about this situation?