Stephon Marbury to Mistress -- I'm Not Paying You Any More Hush Money

Ex-NBA star Stephon Marbury is refusing to pay another cent in hush money to a former mistress -- who worked as his private chef back in 2006 -- claiming his ex-lover isn't entitled to any cash ... because she blabbed their little secret to the world.

You'll recall, the mistress -- a woman named Thurayyah Mitchell -- filed court docs back in October, trying to force Marbury to make good on the $300,000 he allegedly owed her as part of their confidentiality agreement.

Mitchell claimed Marbury -- who's married with kids -- agreed to pay her $900,000 in exchange for her silence regarding the 2006 affair, but stopped making payments in 2010 ... after only coughing up $600,000.

The arbitrator ruled in Mitchell's favor, ordering Marbury to pay her an additional $330,000 -- but now, he's refusing to pay that sum.

Marbury has just filed legal docs of his own, insisting Mitchell gave up her right to that money by publicly filing court docs that detailed her affair with the basketball player.

According to Marbury, the documents violated the confidentiality agreement because they were filed publicly rather than under seal.