Danny Amendola just word-vomited an ESSAY about his relationship with Olivia Culpo -- venting about why they broke up, bragging about their "f*cking crazy" sex ... and bashing her new love interest.
The NFL player started off his IG rant talking about how and Olivia have polar opposite views when it comes to fame and social media.
Amendola says he's a private person and had a problem dealing with Olivia wanting to live her life in the public eye ... saying it was a "fundamental difference" in their relationship.
"Olivia chooses and wants to be noticed on the internet and in Hollywood to make money.