From the in-game Book of Fables
Snow White may seem cold, but this stems from her life of mistreatment and abuse back in the Homelands. After escaping assault and imprisonment, not to mention and an attempt on her life, she married Prince Charming. It wasn't long before Snow discovered that Charming cheated on her with her sister, Rose Red, and she divorced him.
After the Exodus, Snow focused her attention on setting up a safe haven for Fables in the New World. She now serves as Assistant to the Deputy Mayor of Fabletown.