DH has low sex drive...

We've been together two years and I've always been a sexual being. I want him all the time and go out of my way to show him that I do. But no matter my efforts (lingerie, offering no-bs favors, kissing, touching, etc.)he has no interest. I mean, has your SO ever turned down oral sex on a reg. basis?? Our relationship is great and healthy otherwise. And I'm pretty physically fit. I don't understand his lack of interest that has very suddenly developed. Anyone else have this problem or have tips/solutions?