If you really love your girl, then no reason for you to break her heart or make any revenge... it is just a matter of good communication, mutual respect, trust and sincere love for one another.

I think your girl loves you also but she maybe not that showy and expressive of her feelings for you. talk to her nicely and ask bluntly if she still wanna continue the relation with you or not. respect whatever her response may be, even if it's bad or good, accept the fact. That way, both of you will be free from hurting each other and the best thing is you and her will end the relation and the full respect will "remain" for both you and her.

Speak up! talk to her frankly and everything will be alright..Insha Allah