Mr. I went through a similar situation for mine and H's wedding anniversary in October. I decided that while the last 6 months of my M pretty much sucked, overall, the other 2 1/2 years were pretty good. My compromise to not being with H to celebrate (or commiserate) was to go out to dinner with my dad and have a great steak dinner with someone who loves and respects me openly. Just a thought... Maybe you and your S and D could make a special meal and you don't even have to share the reason why with them?
