Eating me out, Husband not going down

Hello everyone. I have been with my husband for 9 years now. he has only tried to go down on me twice and its only ever a tongue flick or two. Then he just freaks out and stops. I go down on him almost every time before sex and sometimes just for the hell of it. He says he has a fear of it because his brother got a disease from his wife. But could there be another reason. I mean he was very inexperienced when we first got together. #oralsex #goingdown