Should I pay for a car that was given to me?

My mother gave me a car when I was married with my wife and it was in both of our names on the title. It said E. Hurd or A. Atha-Hurd. She moved in with another man that had a car and I did not have a car so I went to the dmv and got the title in my name and got the car key and went and got it. Should I have to pay her for the car that my mother gave me? I pay her $100.00 a month for the car when it was given to me.