I'm having some difficulties with my husband that followes Khameini and Sistani.

I have been raised not to eat any seafood that doesn't have fins and scale. and as a result I've never eaten shrimp and prawn. The country I live in doesn't have a separate word for the 2 animal and they're both called Prawns which might be the reason why. My husband however eats both and it makes me upset when he does. I know many scholars say its makruh which to me is enough reason to stay away from it. I don't like that my husband eats it which I've made clear to him but he says its halal

Eating shrimp and prawns is halal and there is no issue with that

I understand you might not be comfortable but we are governed by God’s laws not our desires or thoughts.

Yes we should only eat fish that has scales except those that have been specified like shrimp.
See first question