I'm wondering why he needs your copy back; if he gave you the draft, I would assume either he or his lawyer has the document saved? That's neither here nor there, just odd.
If it were me, I'd give him the document back with no questions/comments. However, I would make a copy for myself first (but not tell him this) so I could make side-by-side comparisons of his changes when you get the new draft.
There is no sense in mind-reading what it is he wants to change. He may want to be more generous or he may want to ask you for more. It will be interesting to see exactly what he has in mind.
In any event, I still think separating finances sooner rather than later is a good idea. If you reconcile, you can easily change this. But as I read somewhere recently, we all need to have a little "f-you" money tucked away for safe keeping. You never know when you might need it.
