Why Do I Keep Forgetting My Wife's Birthday?

I have to admit, I’ve found myself forgetting my wife’s birthday more than once in the last few years. It’s not that I don’t care; quite the opposite, actually. Every time it happens, I feel guilty and worried about whether she feels unappreciated or taken for granted. Despite this, every year seems to catch me off guard like clockwork. Is there some deeper reason why my mind blocks out such an important date? Am I overthinking and just letting stress cloud my memory, or is something else going on here? I would appreciate hearing from others who might have similar experiences or any advice they have for how to avoid this in the future.