How do I break up with my boyfriend?

Me and my boyfriend are both 15 and go to the same school, we've been dating for a year and 2 or 3 months now and he seems to be drifting. He's not very ertive on things and he's very indecisive. I'm also very afraid to break up with him just because he's a bit sensitive and.....im his first girlfriend. I sometimes bring it up to him that he's not "wearing the pants" in this relationship, meaning that he should be the leader. I've just been considering breaking up though, I really do feel that "spark" there i just wish he could step up.