I am desperate. How do I get my girlfriend back?

My girlfriend has dumped me for the most stupid reasons. She says that I have been cheating with dozens of other girls. This just is not true! I have only been cheating with five or six or a few more, ten at the most. And she says that one of the girls was her sister and that made her really mad. But that is so stupid. What is that to do with it? And she says I am only interested in her for her body, which is NOT true. She is an awful looker and I only hang around with her because she is well minted and I rely on her money. If she will not have me back, I will need to get someone else to help me out or in the worst case, I will have to get a job. That would be terrible so what can I do to get her back?