Could my husband go to prison?

My husband pled guilty to theft by extortion to avoid worse penalties. He got mad at another guy that was trying to steal me away from him and he threatened him on the phone. The other guy taped it and apparently it seems in AZ that that is enough. My husband didn't touch the guy or get any money. The money was for divorce (bills). The pre-sentence lady and the Public Pretender said that he would pay just a $500 fine and no more than 6 mos. probation. They don't guarantee anything though. When we go to court if the judge says anything different than agreed, I think we can go to trial. Not sure though.