I am so sorry that you received that call. I don't understand why the OW's parents thought you should know except for the children. It's no longer your worry what happens to him and the OW. It's really a shame what destruction they create as they exit their former lives.
I hope you are doing okay. Yes, you have moved on...
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.