I have a couple of responses, who gets which response depends on who they were to the marriage.
1. We are getting divorced because I didn't like his girlfriend.
2. We had a difference of religious opinion, he thought he was God, I disagreed.
If I tell someone (I don't know well or I know they are a gossip) I am divorced and they ask "Why?" I ask "Why do you want to know?" THAT usually shuts them up pretty quickly.
There was a time I didn't want to tell anyone... I felt like it was my fault and I was humiliated and embarassed. Till I realized it wasn't MY choice for him to cheat. It was his. I had no responsibility in his choice to cheat.
Then I felt like I was telling everyone and anyone... even the UPS guy got an earful one day!
The pendulum swings and eventually rights itself to somewhere in the middle ground.
It is a process and sometimes that process isn't so clearly marked.