If my ex-husband and I have a car that is registered in my name with title in both names, who gets the car?

What does your divorce agreement or decree say?  Who was awarded the car in the divorce?  You need to figure this out before you can act.  If the car is titled to both of you then it is joint property still.  I am assuming by the tone of your question that he has possession and still drives it and you are worried about it all.  You should be worried.  See what the facts of your divorce la out with respect to the car and then seek legal help in ironing it out.  You may need to go back to court to get help if your ex is not agreeable to settling this matter between you.  But do not just go and take the car at this stage.  Good luck.