Yeah, I agree - communication is important for a good sex life for both of you.
He may have reasons why he's not comfortable with it, some that you can address, or not. Then you have to decide what to do from there.
If you're giving him oral sex, though, he should at least try for you unless he has some significant reasons why he won't.
As stated, you'll have to ask him why he doesn't want to.
In the meantime, I suggest wearing loose clothing (no tights/yoga pants), eat a very healthy diet, drink water only and shower before sex. This might help reduce odor and bad tastes. Shaving/waxing will also make your privates more inviting for that activity.
You'll have to ask him. If this is something you'd like him to do then you need to ask him why he won't. Be prepared. He may tell you that you have an odor and a taste. Then you can talk to your doctor about that if it is odor as the issue as bacteria can be the cause. And some men just aren't that into it but you can tell him you'd like it so he needs to try. Compromise in your sex life together is important.