Question is - how are you going to react now, knowing it?
How do you feel now, knowing what you know?
Your post suggests that a few things you suspected have been borne out...
For a good while IMO your GALing activities have been yielding very positive changes - for you...although sometimes its been difficult to extract that against the background of your thoughts and observations - but hey - we've already acknowledged that's just how you like to be on these boards...
Perhaps this night represents something significant in your sitch - you and I have been musing for a while how long we would be able to stick at it...
For you now - it would seem that on the face of it there's everything to play for... but thats unlikely to be realised for a while...and could need quite a bit more GALing consolidation...and for definite would need a long period of reconnection / renegotiation.
I think now Ali - more than ever, you need to take some time to consider your terms of re-engagement - just so that you're prepared if the opportunity, should you decide to stick out for it, comes along...
IMO - this is going to be one of the most difficult periods you'll face - before you were DBing like fury, with half / no hope. Now - you've been given some hope...and its a bit like reaching the end of a long walk - there's still a good way to go, but you relax a little and thats where most accidents occur!
And most importantly, don't forget that there is a pretty widespread view on these boards that the best path to reconnection is by "drawing" your ex back to you...and that although its longer winded, its very much more successful...
Sounds to me, from what you've posted, as if ex might be tentatively stepping onto that path, although he's being careful to make sure that you can't see - just make sure that you don't spoil things by rushing out to meet him at the first sign!