First off I totally get where he is coming from and most ppl think you move in together to "bed" together. Not even sure my partner would have agreed to that in the beginning (they came from the if you love me you'd want to spend every free second with me POV when dating.
But more importantly I really get where YOU are coming from. And especially as you get older it's amazing how many ppl don't have a traditional sleeping arrangement anymore.
In between our different work/school/life schedules, kids, snoring, insomnia, alarm clocks/snooze alarms, different internal temperatures, blanket hogs, stress ect... at the end of the day sometimes you just need personal SPACE! "sleeping together" can RUIN an other wise awesome relationship.
Chances are even if you were stuck in a 1 room apartment you'd end up crashing on the couch at night anyway while watching TV, so mine as well have a spare room if you can afford it. And even better get one with 2 bathrooms! (I know from experience) Hopefully letting him read these responses will assure him it's not him, nothing personal, it's you and there is nothing wrong with feeling like you do. I can not stress enough how much I get where you are coming from.
If you want to move forward chances are you're eventually going to have to move in together so mine as well find out now if you're incompatible then 5 years from now & thinking oooppsss.