It can be hard living with a "challenged" eater. My husband hasn't eaten any red meat or red meat products in 35 years. Not ANY. So we eat vegetarian, poultry, & seafood, but even then he doesn't care much for certain fish like Bluefish or Mackerel. He also doesn't like onions or celery.
I cater to him as much as I can, but only to a point. I LIKE onions & celery, & lets face it, there are very few recipes that don't call for some onion. What I do is buy sweet onion varieties, chop them small, & cook them down. If they're not cooked down enough & he picks them out, so be it. I really don't care. I do the same thing with celery.
Your husband, however, sounds a lot worse than mine. Mine is very good about eating pretty much all vegetables, & with his "no red meat" edict, we probably eat a lot healthier than a lot of people. And he has absolutely no problem if I feel like having a steak or lamb or something. He just cooks for himself. He's really very accomodating.
If I were you, I'd just start cooking what "I" wanted to eat, & hope that my husband grew up from the "little boy" he obviously is & at least start wanting to try different things. It really is juvenile to not even want to try different vegetables - I mean, he's not going to die - lol!!!!
When my brother & I were growing up, my parents were very adventurous cooks. While they never forced us to finish anything we didn't like, we absolutely HAD to taste something before we decided we didn't like it. That was non-negotiable. It was a strict rule that "you can't just decide you don't like something without tasting it". We both grew up enjoying pretty much everything the planet has to offer, thanks to my parents.
I have to agree with Tattrat - cook the healthy foods that YOU want to eat. If he doesn't, he can pick thru & eat what he wants or cook for himself. Life is too short for that kind of nonsense.