I feel your pain. Sometimes my husband forgets too. Once he was supposed to do something and he said we NEVER spoke about it but we did . . . via text. LOL I had it all there and took my phone to him and said "what's this then?" He stared at me blankly. He literally had forgotten. He also has a stressful job. He also doesn't always let what I say 'sink in'. It's annoying. He also has some processing things I suspect because although he's very intelligent, sometimes in conversations he gets confused. We can be talking about a person like say, my sister, and that's the only person we've been talking about and all of a sudden he will look at me blankly and say 'who?". He gets lost. Or I'm so boring he drifts off. lol. Anyway, annoying.
But I'm wondering if you think this is more than that. If something deeper and neurological is going on. How old is he?
Stress affects memory. I find when under acute stress I have memory loss. I have had with serious chronic stress twice. Both times my stomach acid depleted and I developed iron deficiency anaemia. Stomach acid is essential for vitamin B12 absorption but in my case I cannot absorb vitamin B12 (autoimmune pernicious anaemia) so I need sublingual B12 spray daily. I had severe memory loss from this deficiency.