I don't have a great head for remembering specifics, so a while back I used an app on my phone each morning to record whether any sex had taken place the day before. It takes literally a second to respond to the reminder, and a smiley icon means good and non-smiley bad.
It started because I was unhappy with the lack of frequency and wanted to know what say the average per month was without guessing. Fast-forward to now and I now have several years history recorded.
I'm not sure I would ever share this info with my partner, as I have an unease about what it possibly says about me.
Any thoughts on either the concept or what you would say if your partner told you they had done similar?