I never understood people who take holidays like these so seriously to the point where they’d rather cause a serious drift in the family than take 5 minutes to be disappointed and then move on with their lives.
I actually think, as harsh as this sounds, it’s really quite sad to plan your own Mother’s Day celebration. Especially a month in advance. Surely it’s something people choose to do for you?
If your son wants to celebrate with you I’m sure he’ll call up the day before with a gift and a card or something, or invite you out for lunch another time. Which is a completely acceptable compromise. His priority, quite rightly, is his wife.
Grief is not linear. I’ve seen some people get over losing a loved one within a few days. I’ve seen others never get over it, and they’re absolutely bereft every single holiday that rolls around. Both of these, and everything in between, is completely acceptable. You don’t get to dictate how someone grieves.
Your son not showing to his summons for dinner doesn’t mean he doesn’t love you or appreciate you as his mother. It simply means that he needs to be there, as a support, to his wife who will likely be upset on the day.
Personally, the idea of me demanding someone comes to a dinner to celebrate myself while their partner is at home, upset, is really horrible. I could never do that to someone and sit there and enjoy the lunch. Similarly, I couldn’t sit and enjoy lunch while someone is very obviously fragile at the end of the table.
It wouldn’t be for me, personally.