I can't see how it could be that bad.
But, have you tried taking a shower before having sex? Or have you had oral sex while in the shower?
I might get lambasted by the ladies about yeast infections and whatnot, but has he tried eating Altoids or some breath mint while going down? Have you tried flovored lubricants?
http://www.condom.com/oralsex-flavoredlubes.html
The other thing is maybe he doesn't know how to do it right? Or is afraid that you think that he doesn't do a good job. Or if there is a lot of hair down there, it isn't as easy.
I don't know if it works or not, but maybe by changing your diet or by drinking more water, you could change the taste?