75! Take a bow, please. Not many are lucky to celebrate their 75th wedding anniversary, so you should be terribly proud of yourselves for being with each other for all those years. The official theme for this year is diamond. I'd urge upon the jewelry again. A ring, a pendant, earrings or simple diamond studs. Awesome, awesome.
But, at times, material things aren't always the perfect choice for the occasion. In the end, it is up to you to decide what kind of gifts you'd like to present to your husband, and basically, make his day. And remember, whatever gift you present to him should be something he doesn't already own and can utilize it on the day or in the future.