No, he's trying to regain the freedom and space he had before you all moved in together. And that's a problem. Though I doubt he's trying to play the field, it's highly likely that he's having reservations about your relationship and he just might be trying to head in the direction of a separation.
He might say that he thinks you all need your space in order to keep the relationship new and fresh. While I'm sure that's plausible, I'm also sure that makes no real sense for somebody interested in progressing the relationship to the next level. You can find ways to keep it fresh from right across the room. You don't need an actual new apartment to do so.
If I were you, I'd ask a lot of very pointed questions about your relationship and why exactly he feels the need to move out. If he says he's just not feeling the way he used to, then you might as well face the fact that it's over.
Look at it this way, this guy is interested in INCREASING his monthly expenses just for a little more space? He is not happy where he is and is doing something about it.
I never moved in with my wife until we were married, and I only stayed there on the weeks her daughters were at their father's. For a while, until she stated her offense at it, I'd actually get up and go home in the morning before work. Even on the weeks the girls were home, we'd spend dinner and the evening together, and once the girls went to bed, we'd watch some TV and then I'd head home.
However, if you moved in together and he suddenly feels trapped and is looking for more space, I'm with Panama. He's moving the wrong direction.