Note: This was originally a reply writeup to the original top node, from a noder wondering why his girlfriend was upset that he remembered nothing about their visit to Hay Bluff, and bemoaning this fact.
Part of having a relationship is having shared memories. That time you walked out on top of Hay Bluff was wonderful to her, and she thinks it should be meaningful to you too. However, without communicating this fact, it is unlikely that the average other member of the relationship will realize this. Good communication is essential to a relationship.
In order to ensure stability, I decided it was wise to ask my then-girlfriend (now wife) to tell me which dates and things were important to her. This is actually a wise choice. The odd thing is that I'm the one who remembers all the days of note. I guess she's just absent-minded when it comes to "historical" dates.
BTW, not paying attention to an SO is relationship suicide.