I've been thinking about the whole reattachment thing and how frightening it can be for the LBS.
I think for the LBS (or just following an affair) it sometimes takes time to be comfortable again. We go through some really deep pain and even if the WAS has had an epiphany and realizes how much they love their spouse and family, and is thankful to be accepted back, it's still frightening for the LBS.
I've noticed my husband being a little more unusually nice lately. There's a little extra concern for my feelings and I have some of the same feelings you're having. What I figure is I'm going to try and be appreciative of his efforts and just continue working on our friendship. It's just going to take time, and probably for you too. And you can share that with your wife.
My guess is it's almost impossible to jump back in because natural self-preservation holds us back. If that pain of what happened was so intense (and I know it was for me) then the brain or mind will automatically try to protect us.
There is no arriving, ever. It is all a continual becoming.