Hilary Duff has finally pulled the trigger on her marriage, filing for divorce from hubby Mike Comrie ... and it looks like Mike's wild night in Bev Hills was the tipping point.

Sources close to the couple tell TMZ ... it's NOT a coincidence Duff filed her docs a day after the Daily Mail reported Mike was drunkenly propositioning women at Mastro's steakhouse in Bev Hills. Hilary -- who hired attorney Laura Wasser -- cites the usual irreconcilable differences as the reason for divorce. She lists the date of separation as January 2013.