Does he masturbate? If so, that may be satisfying his sex drive without intercourse. Masturbation is fine, as long as it doesn't interfere with someone's regular sex life.
Could he be depressed? One of the symptoms is low-libido. Does he have any other symptoms of depression? It could also be due to some other underlying medical issue, like a thyroid imbalance or something. Ask him to go to the doctor and get a physical to make sure everything is alright. When you do have sex, does he get a full erection? Does he have any difficulty with ejaculation or orgasm?
Many couples don't have sex until they get married (I'm assuming that's what you guys did, since your story started with your honeymoon). However, some people are also raised with a lot of guilt and shame surrounding sexuality. They are taught that it's dirty and shameful, something that should never be talked about or even thought about. It's only for procreation, and that's it. Maybe he just can't bring himself to think of you in a sexual way because you're his pure, beautiful wife. I know this sounds extreme, but some people really do think that way. Was he raised in a very strict or very religious environment?
Could he have been sexually or otherwise physically abused as a child? That can also give people (men and women) an aversion to sex or even to just physical affection/contact in general. Is he otherwise affectionate? Do you hug, kiss, hold hands, say "I love you"? What does he do when you try to be affectionate in a non-sexual way? Does he turn away from you? Does he recoil?
It's understandable why he would be embarrassed about this, regardless of the cause. Sex isn't everything in a relationship, but it is very important because it helps build the bond and create intimacy that carries over to the rest of the relationship. Without it, partners can feel unloved and lonely.
I think it might be time to consider couple's counseling. I would suggest a sex therapist, but that would probably be too far too fast, especially when you don't really know the reason why he isn't interested in sex.
Please know that you are not alone. We have seen many other women on this forum with the same issue. I would encourage you to seek out support from other women who are going through the same thing you are.
If you have any more questions or information, please post again. If you just want to talk or vent, this is a great place to do it. I wish you all the best. I hope you can at least get your husband's cooperation in starting to find the cause of the problem. Good luck.