Oral sex ?

My husband and I have been together for 16 years (married 3 years). I always give him head to warm him up. He loves when I give him head! He has only gone down on me about 3 times in our whole relationship. I want him to start being more playful and start rubbing me more and also go down on me. I have mentioned this too him and he said he doesn't like going down on me. He doesn't like it. I wouldn't want him to do something he doesn't want to do, but I want him to go down, and have more fun, instead of just plain sex. What should I do?