D'Amico, who is played by Ricky Martin in the upcoming FX series, told The Guardian he was not consulted prior to production, and is not happy with one particular scene, which he's only seen a picture of so far.
"There has been so much written and said about the murder, and thousands of suppositions, but not a trace of reality," D'Amico said. "The picture of Ricky Martin holding the body in his arms is ridiculous, maybe it's the director's poetic license, but that is not how I reacted."
D'Amico, Versace's partner of 15 years, would prefer the crime to be left out of the spotlight, too.
"So much has been fictionalized. Unfortunately Gianni died, unfortunately this guy killed him, unfortunately it happened: but now, let it drop," he said.
D'Amico was inside the couple's South Beach home when Versace was shot dead on the steps of the mansion upon his return from a nearby cafe.
"I felt as if my blood had turned to ice," D'Amico said. "The house had stained glass windows so we couldn't see what had happened from inside, so we had to open the gate. I saw Gianni lying on the steps, with blood around him. At that point, everything went dark. I was pulled away, I didn't see any more."
D'Amico also said that the incident led him into depression that lasted a number of years.
"I had never been through a depression and never saw a therapist as I was advised to: why did I need to tell someone else what had happened when I knew I was this way because Gianni's death had torn me in two? I was in a nightmare, I felt nothing and gave no importance to anything … the house, the money … because it felt false to have expectations of life."
"The Assassination of Gianni Versace: American Crime Story" will premiere on FX in early 2018. Édgar Ramirez stars as Versace, Penélope Cruz plays his sister Donatella, and Darren Criss plays serial killer Andrew Cunanan.