Please i need advice im being torn apart from the inside with this girl?

Christ, mate, you need to ditch her. You sound like a decent guy, and you honestly deserve a lot better than her. She sounds like she's addicted to sex and drama. Next time she comes to your place looking to spend the night, imagine her sleeping with some other guy, and kick her out. Seriously, go find some other girl. I know she tells you she likes you and stuff, but that's just words. Her actions are proving what an untrustworthy, slutty, flake she is.