A pretty, bored young noblewoman who flirts with Dorian at his country estate. Being attractive and younger than her husband, it is obvious that she will flirt with such a handsome young man of almost her age.
Being a very clever and pretty young aristocrat, she nearly matches Lord Henry in conversational wit. She freely and lightly admits to numerous adulterous affairs and flirts with Dorian at one of his parties.
We have to admit; we were a bit worried about the charming young Duchess of Monmouth since people who hang out with Dorian tend to end up dead or miserable, or both.
What is the most interesting; she is maybe the only woman of the whole book who can play with Dorian and Lord on her own rules, without a fear of being killed, spoiled or something else. She just lived in the way she wanted to, that is why it could become the reason of why she survived.
It is unknown, (even not important) how did she escape – was it luck or wit? But after all, she is a very intelligent lady. She's the only woman that we see who can hold her own against the dagger-like wit of Lord Henry, and she's well matched with both him and Dorian. Who knows, maybe it was exactly the main reason why Dorian wasn’t interested in destroying her? Maybe they knew she is close to them much more she and could ever imagine?
Though she seems to be truly enamoured of Dorian, we get the feeling that there's more to her than meets the eye. As Henry suggests, perhaps the Duchess is simply too clever. Or perhaps she just lucks out, since Dorian dies before he can lead her to ruin.
The Duchess of Monmouth in the Essays