Hang in there. This is awful but it is true that at this point the D is just a piece of paper. It doesn't change anything. I agree that distancing yourself and unwinding a lot of the family interactions is important, mostly for your own sake-- so you can heal-- but also to give him the opportunity to feel the loss.
Sandi had a really interesting bit of advice on someone's thread-- maybe Phoenix?-- about how to act with loving detachment. I'll try to round it back up and link in for you-- thought it was really helpful.
Have you responded to him yet? Seems like a good opportunity to be calm and say OK. He's probably expecting you to be sad and disappointed.
HUGS.
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing
