How can I get my boyfriend's friends to leave us alone?

Ok, so i am going out with this guy, who I REALLY REALLY like. Now he has 2 friends, a girl and a boy. The girl flirts with him, and clearly likes him, and acts like my friend, but she has been a known backstabber. The boy is just plain annoying. Take today for example. Me and my boy friend are going to the movies after school tomorrow, and he said he would deffinetly be able to go, and the two friends were there. Well that was it! The boy begant o pout and said, “How come I am not invited!” My boy friend said, “Oh! Sorry! I’ll ask my mom if you can come.” Ok, well my boyfriends friends are always following me and him around, and i am thinking can I have one two hour movie ALONE with my boy friend! Then at the end of the day we meet at a certain place at school. My boyfriend comes over and guess who is with him! His two friends. Then the girl that is his friend starts a conversation with my boy friend and is flirting with him and next thing I know i am totally pushed out of the trio. This is not the first time, it’s happened ALOT. Like when my boy friend is 5 feet or more ahead of me and with his friends, when we were talking like 2 seconds ago. What should I do!!! I really don’t want to start a fight!!