Rain - Yes, you should flat-out tell him you need space. It is positive that he's speaking in future terms, but in DB world, it's all about what the WAS does that is the true indicator of their intentions.
I think you could use some time to figure out what it is you want. He really hurt you, and you need to figure it all out. If you needing space makes him run away again, thank your lucky stars it happened sooner rather than later. How incredibly selfish would he have to be to not want what is best for you?
Wait. This is a WAS...LOL OK, they're not known for being selfless, but until you know what YOU want, for certain, you don't need to be working on anything. It wouldn't hurt him to have to spend some time wondering, anyways.
That is my opinion. It is not a golden rule - just my quick thoughts on your (to me) very reasonable request.
