Regarding the Count of Monte Cristo, does Mercedes leave her husband for Edmond Dantes?

No, Mercedes does not leave her husband for Edmond. After her husband commits suicide, Mercédès renounces her title and her husband's wealth. Helped by a monetary gift from Monte Cristo, she goes to live in the small house in Marseilles which was once owned by Dantès' father. She plans to spend the rest of her life in prayer.