You need to file for divorce and ask for use of the vehicle. The court can grant you use of the vehicle during the time you are getting divorced. You can also ask for spousal support (alimony) and child support if the child is his. Normally the court will grant you use of the vehicle and may require him to continue the insurance especially if he has his own vehicle.
Sign up to receive a 10-part series of useful information and legal advice about the divorce process.