One of the things I always remember about my ex is the obsession with her birthday. We celebrated her milestone birthday 5 times, but she remembered the one thing she did for her “big” party. Something that was completed in 30 seconds, but it was something she obsessed about and held against me. It did’t matter that she had 5 parties, and at her ‘big” party, she was the star while I did all the work getting there 45 minutes earlier, arranging for her cake, ordering, etc. She remembered those 30 seconds she took to send out an email invitation.
I then remembered (after I had discovered her affair but not confronted her yet), that her Affair Partner wanted my wife to send him a birthday present.
This video will explain that behavior.