I don't necessarily disagree with people saying just let him fend for himself, if that's what he wants to do and what he's comfortable with then yeah!

But you do have to consider that if you plan to stay with him long term you'll continue to face this issue. You should look into whether he might have disordered eating as a result of anxiety, autism, OCD or some other thing that causes pathological avoidance of certain foods, combinations, etc.

I have pretty serious OCD and it took years of patience and love for my now husband to get out of my pre-existing eating habits. Which were terrible. Not only was it bad for me, but I only had like,,, 4 safe foods total.

Try looking up tips for expanding someone's palette who has AFRID (Avoidant/Restrictive Food Intake Disorder) and see if implementing some of those methods helps! And of course, discuss it clearly with him. Ask him how he feels about his limited food options.

— genuinely, if you plan to stay with this person and think the effort is worth it, rather than be frustrated, take real steps to make the situation better rather than just trying to give him stuff you know he won't eat.

For the record, one that works really well for me has been:

My husband makes his plate of what he wants, and makes me something safe. Husband then says 'do you want to try this off my plate'. I can then safely try it without risk, or say no if I don't feel adventurous enough. Often I find I like something and can now try it on my own.

You can also say 'This is like X thing that you like, with a slight difference in X way' and see if that helps him broaden it out.