Anna, it's funny and strange isn't it exactly how love makes worlds available to us? His space isn't the space you would necessarily have built for yourself, nor is it somewhere you might choose to go. But you can imagine the way it surrounds him, the way this space (which might be strange when empty) becomes something different when he is in it.
Now there is the difficult matter of moving from love to life. Living together entails a certain common construction of existence. All of a sudden the strange world which he's allowed you to enter has to become your base of operations, and vice versa. This is much harder. I personally think it's easier if a couple moves into a new place together, rather than one person moving into another's space, but this isn't always practical. Try to find a house or apartment with some kind of variation -- a nice den, a nice porch. It doesn't take much: even if you sleep with the curtains closed for him, you might just find you need a room where you can go first thing in the morning and get sunlight.
Provided you don't work from home, you can also try to incorporate a certain variation into your daily routine (join a gym with big windows, work in a skyscraper and get to work early some mornings, and so forth).
My experience is that everyone needs certain things to make them feel at home in a space, and that those things are more essential than others tend to acknowledge, but also smaller and less difficult to satisfy than one usually thinks. To state the obvious, communication is key.
As an architect (cum psychologist) I might be able to help. I would propose each your own bedroom.
His in the basement, yours on the penthouse. Living quarters in between. Visiting hours to your convenience.
This way, you may be able to enjoy each other's company longer.
Good luck and long live ''love'' (or attachment, symbiosis, fusion, patnership or whatever you want it to be)