A man with Alzheimer's forgot he was married, and fell in love with his wife all over again
https://edition.cnn.com/2021/06/26/us/alzheimers-couple-married-twice-trnd/index.html
In the case of my grandmother, who also has dementia, the memory structure is different from this case. She knows existence of her husband. But, she forgot that her husband has already passed away. Judging from when she got married to husband and when this couple married, I guess those who married at younger age have less possibility to forget their partners even after having kind of dementia.
