In my experience many men just do not put as much emphasis, or give much head-space on birthdays and other 'special' days.
Sorry but I don’t agree that that is true of all men, maybe it depends how they are brought up, what their dad is like, whether mum has always done wife work. I never did it all, DH does all his family birthdays, has never forgotten MD, my birthday, anniversary, etc, even the first year together when he was working abroad.
I have an adult son, back at home after uni for 4yrs, who has never once needed reminding about my birthday or Mother’s Day, similar for FD and his dad and sisters birthdays. He still knows when my mums birthday was, 5yrs after she died.
I have just had a birthday and both he, DH & DD asked me what presents I wanted (not much, but I still got some nice bits) and what I wanted to do, a few weeks in advance. He and his dad baked me a scrumptious cake.
Similar with Mother’s Day, we had been discussing maybe having an afternoon tea delivery. DS did all the leg work of contacting companies for food options (we have a vegetarian plus some allergies) and then making the booking, after consulting with the rest of us to discuss choice of sandwiches and cakes.
He also cooked Mother’s Day dinner, as DD had done breakfast (we had afternoon tea on Saturday). They both bought me a card and small present, as well as the afternoon tea.
As a pp said, no one can forget MD, even in lockdown! My DD works in retail, her shop was heaving on Saturday.
In your case Op, your partner chose not to mark your first MD, which shows how little respect he has for you.