Kim Kardashian wrote an emotional email to her extended family members early Monday morning -- giving them a head's up that she was filing for divorce ... and apologizing for "jumping the gun."
TMZ has learned ... Kim emailed several people on her father's side of the family in the hours before she filed the documents with the court ... saying, "I would rather you hear it from me than someone else or the news."
In the letter, Kim explains, "I know this seems crazy ... I've spent the last few months struggling with my marriage."
"Kris is a great guy but we come from such different worlds and he isn't what I thought when we 1st met."
"I'm embarrassed that I took everyone on this journey with me and had this huge wedding. But I have to be happy, so I have to let this relationship go. "
Kim's reps had no comment.