You could seek help and advice from Relate, either as a Couple, or for yourself as a partner. This can be via literature, Books, leaflets, contact numbers for advice lines, or by seeing one of their trained Counsellors face to face. Your Husband may also find it useful to be checked over by a urologist, and any physical causes treated or ruled out. As a Diabetic man, he would also be entitled to free treatment on prescription, of which there are many types, not just Viagra. The chances are that he's feeling very angry with himself that his body is letting him down in this way, and is feeling unworthy of your affections, hence he has given up somewhat as he sees himself as a bit of a burden, and doesn't want to pester you knowing that he has little chance of giving you full lovemaking like he used to do. Relate can help with these feelings too, as part of Couple counselling, and setting small tasks for you both to try as 'Homework' between sessions, which can be very helpful.