I hate it when he tries to reassure me. It either sounds minimising and impatient or patronising. And I know he doesn't mean to be, he wouldn't do it on purpose.
I once pulled him up on it and he said "When will I learn? Reassurance is never reassuring" but he still does it sometimes.
Like about my loved one who had a medical emergency. He was trying to be reassuring about their health, but I don't see how he could possibly know, so it seemed like a waste of time.
I am planning to have another discussion with him about not trying to reassure me.