Like I said, there's a reason we spent a year getting back together. We've always stayed close friends, and have been in each others' lives for 28 years now (she was 15, I was 17) but there were reasons we divorced (many of which I wasn't aware of when I posted about it 11 years ago.) First we took time to make sure we enjoyed just spending time together, then we wanted to make sure that we'd both grown past the things that caused problems all those years ago. When we were sure of that, we took more time to make sure that we could both leave the past in the past, were over past mistakes, and could approach this not as a continuation of what we had before, but as two different people in a new relationship.
We determined right at the beginning that we absolutely would not tell the kids until we were both certain it would work. We're not willing to run experiments with them involved.