My ex used to do this. And with graphic sex stories. I think it was so I realised what a massive catch he was… As he was an unemployed, alcoholic abuser, he needed all the help he could get in that department.
I figure it’s all about control. “Be a good girl or I’ll just find someone else. Look at all, the women I’ve had before. You’re expendable. And they were all, younger, prettier, thinner, better in bed, etc…….”.