"In the last couple of weeks, I have found myself the focus of an avalanche of negative publicity," Wynn said in a statement.
"As I have reflected upon the environment this has created -- one in which a rush to judgment takes precedence over everything else, including the facts -- I have reached the conclusion I cannot continue to be effective in my current roles."
The 76-year-old former business rival turned political ally of President Donald Trump resigned late last month from his role as Republican National Committee finance chairman, a post he had assumed after Trump took office in January 2017.
Wynn has denied the allegations, first published in The Wall Street Journal, and accused his ex-wife Elaine of instigating the accusations as part of a "terrible and nasty lawsuit" seeking a revised divorce settlement.