<human>: So...This might be very confusing, but I honestly do not know where to turn to or what to do. I am in a long distance relationship of two years, out of high school. I don't want to hear the obvious, "oh LDR never last, just break up and move on." 

I don't want to break up. But we have one issue that always seems to come up. One of my roomates, who I'm going to be rooming with next year, she absolutely hates. She hates him because apparently he annoys her (they don't talk), and that I used to hang out with him too much (We live in the same suite). 
She has told me that she hates him and will never forgive him, and that if I were to room with him next year, that we would break up. We just chose rooms and currently, I am supposed to room with him. I told her this and she is just flipping out. I just talked to him and he was just as confused as I am as to why she hates him.

My real question is whether or not she is being childish and immature? And what should I do?

I can explain probably better through a private message but thank you guys...

Can you succinctly summarize the text in 1-3 sentences?
<bot>: Long distance relationship. Girlfriend HATES future roommate. Wants to break up over me telling her that there is the possibility of me rooming with him.