Well, it's an unclear structure. Putting a comma before and after someone's name is correct if including the name would not change the meaning of the sentence, as in this case. In the case of OP's sentence, it could have implied that Polidori was Mary Shelley's husband as his name, while important to the meaning of the sentence, was included in a list of other people, including Mary Shelley, Mary Shelley's husband, and Lord Byron.

I see the comma now, but Percy Bysshe Shelley was an incredible writer who is studied and lauded, rightly, on his own merit. Anyone reading this thinking Mary's husband is insignificant compared to Frankenstein needs to read Ozymandias or The Masque of Anarchy right now and witness this beautiful, humanistic and liberatory spirit.