I'm yelling at my boyfriend yesterday because of jealousy and insecurity, then he decided to leave me and break up with me just because he doesn't want to be yelled at. Is he right for his decision? Am I bad?

Yes he is right because this is your jealousy and your insecurity and not his responsibility to fix, its yours. Jealous insecurity is a never-ending burden on someone and it gets real tiresome real quick, The funny thing is it creates the same thing you fear, him going away to someone else. The other thing is jealousy hurts you not him and is more likely  than not to be undeserved.