Do you have a super king bed? You're going to need one. And he'll be able to change the duvet cover as easily as you would a single. Never have to change a light bulb or get a set of steps out, either.
Other things to be aware of are;
Tripping over size 15 shoes left out is far more likely because they take up so much space.
You'll never have a romantic cottage holiday. Or at least one without him getting concussion as he walks through a doorway.
Don't let him cuddle up by resting on you. If he goes to sleep, you're stuck there. Always, always cuddle with him underneath or to your side.
Check he doesn't starfish in bed. If he does, there is no escape from limbs everywhere.
Cars. He will have strong opinions on cars, flights, movies and anywhere else that involves seating.
As an ex pointed out once, when you get to over 6'3", you're borderline for needing reasonable adjustments because the world just isn't built for people that tall.