Oh no, LL. I'm sorry.
It's so bloody difficult to feel pressured ALL the time, to have to come up with the "correct"

reassurances that someone who is that needy of it, will even accept.
If I may offer an opinion: It doesn't sound to me like he is asking for objective reassurance -- he's all in his FEEEELINGS, and wants to be assured until he feels reassured. Which isn't wrong -- but when it's constant, it surely is exhausting!
It would seem a little invalidating, imo, to be asked for assurances -- and then to have him immediately announce that, in effect, you aren't telling the truth ("You aren't fine"; "your silence says...." etc.) That is what would make my head explode.
Granted that relationships are hard work and a lot of it -- you'll need to evaluate how much heavy going this one is worth. Wishing you all the luck!
Best,
Chia, really smdh