I'm so sorry...I know what that feels like (remember my sagas?).
Just keep trucking along....you have no idea what is going on with him leaving her, breaking it off. It's gotta be tough (not that you have to sympathize for the fool) breaking off an A with someone you WORK with....geez.
I think when they make moves to come back, we expect ALL contact to be frozen....but we don't take into account that they have to break it off, and that takes a few conversations, etc. Just look at Jokerman's situation, she was calling all the time and I'm sure they talked a bit to end things.
No doubt he is coming back to you. What happened happened, deal with that later between the two of you. For now, let him end things without your interference...JM is right, he has to do this b/c he wants to not out of force from your part, you don't want that either, knowing your H is with you b/c you forced him.
This will come to an end soon. You are in the winning column now, take heart in that. Stay busy, be cheery, and be inviting. There will be a day that you express to H how much hurt he caused you, and how awful it was, and he will be on his knees asking for forgiveness and you will both talk about it all clearly.
Until then, you're still in the game. Put your game face on and keep trucking. You didn't come this far to lose now.