A letter written by Malcolm X to Nation of Islam leader, Elijah Muhammad, discussing his marital woes has gone on sale for $75,000, according to TMZ. 

In the letter, Malcolm X asks his mentor for help on how to deal with his marriage with Betty Shabazz, whom he was married to until his assassination in 1965. He disclosed marital issues involving finances, control and sex.

“The main source of our trouble was based upon sex,” he wrote in the letter. “She placed a great deal more stress upon it than I was physically capable of doing.”

The letter is being sold through Moments in Time, a site specializing in buying and selling original documents by historical figures.

The 53rd anniversary of Malcolm X’s death is February 21.