Well...if you're both willing, then consider going to a sex therapist. Or buy a book on this topic and read up. He obviously has some hang-ups about sex. That could be due to how he was raised or even what religion (if any) he was exposed to growing up. All this is definitely worth exploring especially since you feel it is the one threat to your marriage.
There is something you really need to think about, and that is this --- As we age, our sex drive naturally diminishes some. Then there is always the possibility of physical ailments, thus no more sex. Try to picture yourself much older with a husband who can't perform due to physical problems. Can you live with that?
If I recall correctly, you once asked about sex toys to pleasure yourself. Have you purchased any? There is no shame in using them and doing some fantasizing.
I now understand why you brought up the subject of being attractive. Yes, unfortunately, it's true that there are some who will throw it in your face and tell you that's why your husband doesn't want sex. However, there are many stories of women who have had mastectomies, for example, whose husbands have told them that they still love them and find them attractive. These men are aware that external beauty isn't the only thing that matters---internal beauty matters even more in the long haul. We all lose our looks to some degree as we age. However, internal beauty tends to stay with you for a lifetime.
So...maybe you need to sit him down and have a heart to heart talk about this. See if you can get to the root of his hang ups. Ask him if he will, at least, try to manually pleasure you (either using a sex toy or his finger). If you feel that after having the discussion, that you haven't made any satisfactory progress, then bring up having both of you see a sex therapist and see how he reacts. If he doesn't want to do that (and gives a reason for it), then tell him that you both need to get serious about this and reach a compromise that you both can live with.
You have a lot to think about. I wish you all the best!