Fortunately or unfortunately your divorce in today's society is idle gossip among acquaintances. I don't talk about it. If someone wants to ask me, it's okay. If not, I'm not going to make it the center of my life since I believe that paves the road to bitterness.
If you're going to the reunion, you set the tone. How do you want to spend your energy. In the same way that children model after their parents, your friends from highschool will react in the way you signal them too.
Recently while out with a big group of people after a play I worked on I was talking to people I used to know better in the past. Part of me wondered.. should I say anything about my pending divorce? The answer was no. I don't want my life to be about what was... but what it will be.
Have fun.. and look at the bright side... now you can worry about whether you need to lose weight or not!