Leave my girlfriend?

[Deltron]

To be honest, I don't think your relationship with her should continue.

Obviously, stated by the information you have given, she is not a very trustworthy person. If she has cheated on you numerous times, there's nothing that is stopping her from doing it again.

If this happened to me, I would never forgive that person under any circumstances.

I suggest you move on, no matter how much you like her. Once again, she has cheated on you numerous times, and I don't think that is part of a healthy relationship. You deserve much better.