Spook - glad you are managing to hold it together! I think you might both benefit from some counselling once you both decide that you want to still be together. This will allow both of you to say your piece in a neutral territory with someone who can facilitate this happening.
It really is such early days - he will be very grupmy with you - afterall you've stopped his fun. He'd been having it all for a long time and you have now made him choose. He will of course conviently have fogotton that he should never have got himself into this position!
Don't assume too much about your own feelings at the moment - you just need to let them flow until they settle down - probably weeks not days IME.
FWIW I too sent my exh off and gave him the space he wanted. I too prayed he would return etc etc. However, about 3 months into the whole thing my feelings completely flipped. I realised that I didn't want to waste years of my life knowing that my trust could be betrayed again. So in the end I went for a divorce and have never looked back! I just think I was being realistic about my ability to 'forgive and forget' although I do really admire those people who can mend their relationships and move on, it just wasn't for me.
I hope that you get the answer you are looking for although it will take a lot of time for the dust to settle. Play it cool with him - give him the space but make him realise that its at a cost! You won't be there to be his confidant while he's dealing with losing her - its not fair on you - he has to get through this bit on his own.
You are dealing with two different things at the moment - the actual loss of him from your life (which might be temporary) but by far the biggest loss is the loss of the person you believed him to be. Thats the bit that may never return!
Lots of hugs to you - you are doing well!!