You have been duped but are still fortunate. At least she hasn't falsely accused you. Associating with people like that can ruin your life.
I know someone who was played like this by his girlfriend. He was lucky to only have a year probation and thousands in legal fees. He was facing 5 years if convicted, he plead guilty to a lesser crime. She accused him of assault and theft. It ruined 3 yrs of his life. Later he found out that she has done this before.
If your girlfriend is a manipulative liar and you cease to be useful she could be a big threat.