Can I repossess a car if the other owner loses their license and I am the co owner on the title and the loan?

I was the co-signer on a loan for my now ex fiance' and he has a suspended license. I am on the title of the car. He has been driving around in the car and has been caught by the police once already. He is allowing other people to drive the vehicle and now will not hand me a set of keys or tell me where the he has the car parked. What can I do to save my behind here because he is being very irresponsible