My breathe smells!!!?

so i brush my teeth twice && sometimes 3 times a dayy......i scrub my tounge alot and i have no plaque on my teeth whatsoeverr......everytime i go to the dentist they say my teeth are perfect and my breathe is nothing i should worry about........but im 15.....i have to worry about my breathe........i dnt want my boyfrannn smelling myy breathe....ewww.!.........so help someonee?! please?!!?!