<human>: I've been dating this same girl for two years now, but the relationship just isn't going where I planned it to. I'm in high school so I wanted it to be a more fun and casual relationship. But lately she's been talking about marriage, and being very controlling of me. She's trying to tell me where I can and cannot go to college, as well as what colleges I'm allowed to look at that are close to her ideal schools. My girlfriend is also what many people would consider as a "bitch." This view point had not become apparent to me until our recent spurt of fights. We got over them but I just don't want to deal with it anymore. I have a lot going on right now and I don't need added stress, and as of now that's all she's adding. We are sexually active but not often, maybe at the most once or twice a month. I really want to break up with her but I feel like it would just absolutely blindside her. I don't want to hurt her horribly either... What would be the easiest way to break up with her?

Could you distill the essence of the text into 1-3 sentences?
<bot>: GF was really cool for a while, started becoming annoying and controlling, and I don't know how to break up with her.