Speaking as someone who has been married for 15 years and both of us have health and preference issues influencing our food choices—I suggest you cut your husband loose to fend for himself when it comes to breakfast.
Let him plan what he needs for the shopping list (regardless of who does the shopping), preparation, and consumption. Let him decide for himself if he’s going to start making the right dietary choices and then executing them. Don’t let his needs and preferences affect what you need to to for yourself.
If he’s going to continue to need doughnuts for breakfast, tell him he’s got to do his doughnut storage and consumption somewhere outside the house.
Because you don’t like cereal, have you avoided the cereal aisle so as not to have seen the number of options these days? It’s not how it used to be, there are some really nice mueslis and alternatives to corn flakes and weeties and those sugary concoctions. I’ve got these “lumps” with cranberries and stuff. It’s quite nice.
Have you ever tried bircher muesli? It’s yummy. Oats are soaked in fruit juice overnight and it’s got grated apples in it and seeds and nuts and stuff (if you make it yourself, you can put whatever you like in it) and then you eat it with yoghurt. If you use sweet fruit, it’ll be sweet, but I’m not a sweet tooth, if you use green apple and lemon juice and not add (many) sweet things, it’ll be tart. Greek yoghurt. Yum.
Another suggestion that may (or may not) pass the “no dinner foods for breakfast” rule is bubble n squeak. Leftover mashed potato fried up with leftover veggies. Get it all crusty and have it on toast.
When I was in Germany, they gave us kaiser rolls for breakfast. You could also have cheese on rye bread. Bread for breakfast is a thing in some places.
crepes have been suggested. Yes you can have them savoury with whatever you want. Veggies in a bechamel sauce would be nice for breakfast, broccoli, spinach, some little champignon mushrooms maybe…
(now I’m REALLY hungry :D)
Asparagus makes a tasty breakfast veggie. A poached egg on a slice of non-buttered wholewheat or multi-grain toast (don’t need butter with a runny yolk) and a couple stalks of asparagus on the side is mighty fine.