New York Knicks player Raymond Felton committed ADULTERY during his marriage ... so says his estranged wife in divorce docs obtained by TMZ Sports.
Ariane Raymondo Felton -- the same woman who ratted Raymond out to the cops about his illegal firearm -- filed docs last month in a New York court seeking to end their 18-month marriage.
But in the docs, Ariane penciled in that she's divorcing Felton because of "adultery."
Ariane doesn't go into detail about the adultery allegations ... but in the docs, she does request the judge throw out their pre-nup. It seems she wants the prenup tossed out on the count of the alleged cheating, but she doesn't explain why.
Ariane is seeking "maintenance" -- which is essentially alimony. She also wants Raymond to finish paying for the last two years of her law school education at Fordham University.