Took a loan out for my now ex-boyfriend

I took a loan out for $1000 in order to get my now ex-boyfriend a car. I signed the loan as the vehicle owner, but since we were not living together, we could not get both our names on the title so the title just has his name on it. He claims that he is still going to pay for the truck, but I wanted to know if there was anything I could do to make him responsible for the payments if in fact he falls behind? - Is this your question? Add additional information