I am so glad everything turned out okay for the graduation ceremony. Congratulations to your daughter!
I had a very strong feeling that your xw wouldn't show up. Why? Because they tend to do stuff like this all of the time because they want people to remember that they are out there. In many cases, they tend to pop out around special events and do and say things that put a damper on the event. I honestly don't think they can help themselves because they are so miserable that they want others to be that way too. They can't see beyond the tip of their noses how to get themselves out of their own way. I'm not making excuses for them, but it appears that she's a very miserable and lonely woman who can't or won't get help.
You and your girls are living your lives and that's what is very important. Enjoy the time you spend with your girls because those memories can't be played back at a future date, except in photos.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.