Oh don't feel stupid! It's a lesson learned is all. It's not wrong to want to see the best in people, especially someone you have children with. It takes a while.
My XAH and I tried the whole let's be a big happy divorced family. It lasted about 10 mins LOL. It was weird for my kids too (they told me this later).
Kids can have a life with both. The goal of divorce is that you don't have to spend time w/that person anymore. I know one divorced couple who hang out together all the time. One couple. In the tons of divorced couples I know. It's rare. We all want to be those people, but in reality it's just not likely.
Big hugs!