'Mob Wives' Natalie Guercio -- Boyfriend London Rene Slashed and Stabbed in Nightclub Attack

The boyfriend of "Mob Wives" star Natalie Guercio got knifed in a Brooklyn nightclub last night ... TMZ has learned.London Rene has a huge wound on the right side of his face after the attack in Club Output. He's hospitalized, and from what he told…