Dust Be glad though that he doesn't show up with the bimbo and be proud- that would be worse!! These MLC teenagers are generally cowardly, selfish boys.
I agree with the note to H- definately thank him for the dinner- they love the compliments!! I find after a compliment my life goes smoother for a bit with STBXH.
I know you are feeling badly that he will miss this important event for your D- this is his guilt though not yours. Let him make his own mistakes, I know he isn't acting like an adult but he is one! I also get involved when the kid's feelings may be hurt, and it is just mothering my STBXH - which won't help either of us.
Hold your head high and know that you are handling yourself with dignity and continue to take the high road for you and your D- it does pay off in the long run!