“I haven’t been the kind of friend I know I am capable of being.”

Tupac Shakur dated Madonna for a brief period in the early ’90s, a short-lived relationship that fans assumed flamed out due to their competing schedules, and conflicting lifestyles.

A newly revealed break-up letter, which is up for auction, shows Tupac was worried that dating a white woman was hurting his reputation.

“Can u understand that?” he writes. “For you to be seen with a black man wouldn’t in any way jeopardize your career, if anything it would make you seem that much more open & exciting. But for me at least in my previous perception I felt due to my ‘image’ I would be letting down half of the people who made me what I thought I was. I never meant to hurt you.”

A lot of the letter is redacted, but shows Tupac was also stung by comments Madonna made to the press.

“An interview where you said ‘I’m off to rehabilitate all the rappers & basketball players’ or something to that effect, those words cut me deep seeing how I had never known you to be with any rappers besides myself. It was at this moment out of hurt and a natural instinct to strike back and defend my heart and ego that I said a lot of things…Can you feel me?”

The letter gets dark towards the end, with Tupac seemingly aware that his life was in danger. “I felt compelled to tell you…just in case anything happened 2 me.” He concludes:

“Please be careful Madonna. Everyone is not as honorable as they seem. There are those whose hearts bleed with envy & evil. They would not hesitate to do you harm! Let my 5 bullets be proof of that!”

Obviously this is a key artifact in the short life of Tupac, and of interest to serious collectors. Bidding begins at $100,000.Check out the auction here, and the letter here.