I am to blame for this break up I've never cheated on her with anyone. But she still break up with me anyway. Now the problem is I love her. Now the problem is I keep making the same mistake over and over, now she is fed up with me what should I do to fall for me again

What mistake do you keep making over, and over, and WHY do you do it?? How old are you both?

If you know the mistake you are making, over and over, is the cause of the breakup, it sounds like you missed the boat to correct the mistake along the way.

It would be helpful to know what the mistake was.

Either you change or leave her alone. Think about what your doing and why you do it.