Is a week to fast to move on from your ex girlfriend?

IS a week to fast to move on from your ex girlfriend as much as I love her **** really has hit the fan. I'm with her almost five years I am 22 years of age, long story cut short two years ago she was accused by her room meats EX Boyfriend that she cheated on me while she was on holidays with two different guys, Our sex life was bad enough as it was she says she just doesn't like sex. I tried my best to leave her before but I thought i loved her to much and would be a mistake, long behold the guy she was meant to have cheated on me with there friends on facebook and pictures up of them looking very happy. she SWEARS nothing happened and that the pictures were taken when we were broken up. Dates on pictures don't lie we weren't broken up. Bad enough she's home by half ten on weekends at the age of 21 and she cant tell her parents were together because they think we broke up two years ago, But yet she makes me out to be a psycho for getting angry that she goes home so early and cant tell her parents were together!! Make it worst her parents own a place in Spain were this supposedly happened she'll always be around that guy and she see's nothing wrong with it that i'm crazy that I should just believe her, bad enough she DONE NOTHING TO PROF SHE DID NT CHEAT. Should I just Leave these Five years and try move on?? She is a very Pretty girl and to be honest doesn't dress like she has a boyfriend when she goes out, I wouldn't mind if I was there but when she goes back for college for the third year. We live in different city's and take turns of going to see each other every week. Can you blame me for being paranoid she doesn't try help that. she doest want us to break up. Any advice is very welcomed thanks people.