'Orange is the New Black' -- Writer Files for Divorce ... Show Made Me Realize I'm a Lesbian

One of the head writers for "Orange is the New Black" has filed for divorce ... the logical step since she's now realized she's a lesbian and is dating one of the female stars.

Lauren Morelli just filed divorce docs -- obtained by TMZ -- from her husband of 2 years, Steve Basilone. It's actually a joint petition ... probably because Steve realizes that ship has sailed.

The story is amazing. Lauren began writing for OITNB 5 months after she got hitched. Lauren says as she started writing for the main character -- who had once been in a lesbian relationship -- she saw herself in the character. Lauren says she began to feel like a fraud ... married to a man but clearly gay.

According to Lauren ... as she began writing about Piper's blossoming relationship with the very hot Alex ... "I found a mouthpiece for my own desires and a glimmer of what my future could look like."

Enter Samira Wiley -- who plays Poussey. It's Lauren's new GF.

According to divorce docs, it's all very amicable. She gets her Lexus, her apartment and her sapphire engagement ring. He gets the Mazda hatchback.