I myself would be hesitant to living together as well.
I want to, but i'm afraid that i will lose the ability to unwind and recharge when there is someone else in my home.
If i were to live together with someone, i'd need my own room with a bed, a safe room.
I know that i will, regularly, need to sleep alone in order to get a full energetic recharge, and i also need to be solitary at times, so the aforementioned room will be a must.
The guestroom won't really do, as that room/bed is used by others at times, i will need my own spot; the best way to describe it would be a "man cave", but for a different kind of man.
perhaps offer him the above option? it is not unlikely that his concerns match mine (although i can obviously be wrong), in which case the promise of a safe place to recharge might be enough for him to try living together.