why I felt uncomfortable about the comment:
*I have a boyfriend, I am not single
*My boyfriend wouldn't like it for me to have a male friend calling me "my beautiful" and "my lady"
*It feels like a person saying "my beautiful" and "my lady" is subtly "claiming you" as a sort of romantic or sexual partner with no consideration or consent from the other person. So a bit like psychological manipulation.
Otherwise, since you're a close friend it could have been totally innocent just meant in a friendly, non-romantic loving way. But I didn't know your intent.