He wants to the opportunity to (explore) other "options".
This may be more free time to spend with his friends or pursuing new relationships. Either way you'd be a fool to put your life on "hold" waiting for the phone to ring. Wanting "space" or having a "trial separation" are usually code words for a breakup. If you were "the one" he'd want to spend more time with you and not less time.
It would not surpise me if you started dating someone new he'd suddendly have a change of heart and try to take up (your free time). A lot of men believe "Once I've been there I can always can get back in". Hearing about you being with a new guy will make him wonder if he made a mistake. (Of course he didn't because if he didn't see you as being "the one" it's impossible for him to have been "the one" for you!) Soul-mates means both people mutually value each other as being "the one."