Echoes of Lost Time

I saved my ex-boyfriend's daughter from a car accident, but lost my own life in the process.
While sorting through my belongings, he unexpectedly discovered my diary.
In the diary, he was deeply in love with me, carefully remembering my old scars, and even braving a severe cold to build me a snowman on Christmas Day to make up for my regrets.
In the diary, we never broke up. We even got married, and our married life was stable and sweet...
This was a story he had no memory of.
It was also a deeply buried love he never knew about.