I'm glad your h has agreed to go to the school function. It will mean a lot to your daughter. Please don't worry about the ring situation. A lot of people do not worry about him not wearing his ring. Some people don't wear rings in this day and age.

Keep the focus on you and your family.

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.