I agree that it is important to give forewarning. Receiving D papers without any warning would be a shock. And I think to forewarn is to show care and honour the M you have had. Even if it is to come to an end.
My H emailed me a few days before I received D papers, and I grieved for 24 hours and was then ready for them to arrive. I'm glad he did that and I think it was the right way.
Why would you not forewarn her?
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus