My educated guess is that despite seeming perfect in every logical way, he isn't doing his part to create masculine/feminine polarity. In other words, he's coming off as neuter rather than demonstrating those powerful traits of true masculinity that ignite femininity. Make no mistake. Two neuter creatures cannot "attract" each other. Rest assured you haven't done anything wrong, and there is by no means anything to feel guilty about. What's going on is very real. BTW, "masculine" is not to be confused with "macho"
How in the world are you going to stay faithful to someone for 20 years if you're not attracted to them?
What about him? How is he going to feel in a few years if you don't really want to have sex with him?
What if you have kids? Do you want to teach your daughter that she should expect to marry a guy she doesn't want to have sex with? Do you want to teach your son that wives don't like sex? Do you want to stay married for your kids' sake if your marriage is sexless? if you find someone else who you love and want to sleep with? Unless you suddenly find attraction growing between you two, don't do this to yourself or him.
But MY ADVICE is : Pick out those things that you dont really like about him, as these might be the reason why you find it difficult to love him, If you can live with those things, then you can go ahead, do little work on him, you can still love him with time. But if you cannot live with those things, then, you have to get out of the relationship before it is too late for the two of you. In my own case, i decided to walk on those thing that does not make me to love him the way i supposed, and now, I love him and our relationship holds a bright future.