Ok...how about answering some questions about his background. You've said he's ALWAYS been this way in your relationship, that's pretty telling.
I'm not going to say that your H has whore/madonna at this point (not even close yet), but there are a couple of us on here...who are dealing with husbands who have NEVER initiated, who would allow us to live sexually celibate lives if we didn't initiate ALL THE TIME too....that is why I am asking about your H's upbringing, and his parents (who would be sexual role models as to how he views sex/marriage) etc.
Visit Heywyre's threads...aside from her H's infidelity, let me know if any of it sounds familiar.
"IF", BIG "IF", your H does have whore/madonna...doing as Chrissy suggested would have no effect on him as far as getting him to reciprocate that type of behavior in the future. He might go along with you at that time, but he would still not initiate....unless you threw a big fit, made a scene.....or he felt like he had to do it to check you off of a list, make you happy, or shut you up (no offense Chrissy)....because sex/marriage aren't something he associates as something that you actually do....it's a disassociation. You marry a woman you love and respect, but you don't f*ck women you respect.
If however your H just simply has a low libido that's another thing altogether...BTW, I don't remember if you mentioned, has he ever had his testosterone level checked? If he has a low T-level then that can account for a lack of libido as well.