Long story...he's alleging fraud and breach of contract on Dana's part. Essentially he is saying as part of his guilty plea Dana was to pay him for his silence. Dana didn't and so he can't extort him twice. So he's really just making Dana's life miserable. My understanding is Dana has been married since before the UFC got big and likely does not have a prenup.
See below:
"After the encounter, Ramos was arrested by FBI agents in January 2015 and charged with trying to extort $200,000 from an unnamed businessman, whom the civil suit says was White. Ramos served a 366-day sentence in federal prison following his guilty plea.
According to Ramos' suit, there was a protective order on releasing White's name until the conclusion of the 2015 case. Christopherson said Ramos was under the impression through White's legal team that he would be able to negotiate a lucrative non-disclosure agreement after his guilty plea. But White reneged on the deal in April 2016, the suit said, after Ramos had made his plea.
"The actions of White were fraudulent, oppressive and designed to encourage Ramos to plead guilty so he could negotiate a substantial settlement, which would prevent the disclosure of his actions at trial for the personal benefit of White and his related businesses and interest," Christopherson wrote in the complaint."
https://www.espn.com/mma/story/_/id/28996364/ufc-dana-white-named-extortion-victim-lawsuit