How to avoid my girlfriend ?

Hello,
I am too much frustrated from my girlfriend she irritate me everytime and when I angry on her then she start crying so, plz tell me what excuse should I give to her from which she agree on that excuse and understand me. I am a B.tech student and I have to give time to my study and I also don't want to loose her. So, plz give a convenient suggestion.

Tell her that you need to established before marrying him.so,you should concentrete on your study and it is her duty not to disturb you now because she is your well wisher and your good career will be very much important for her also if she thinks about the future.