ScreeningNotes’s review published on Letterboxd:
"It would be nice if you did it without having to be asked."
In retrospect, it should have be obvious that it would take the specificity of sadomasochism to reach such universal truths about love, romance, and sexuality. Part of the brilliance of the S&M premise is that it foregrounds the performative nature of desire.
The film opens on a scene of a domineering house mistress Cynthia ordering around her subservient cleaning lady Evelyn—but then we see this supposed matriarch reading a card which outlines the ways in which she's supposed to be domineering over the cleaning lady. Then the opening scene plays again, but with a totally different meaning. Cynthia is enacting a fantasy scenario for Evelyn, which is the essence of romance whether S&M or otherwise. We all perform for the desired other in order to satisfy them, but here writer/director Peter Strickland makes the genius inversion of constructing the performer (Cynthia, the dominatrix) as the one who appears to be in (sexual) power but is actually subservient, working to please her partner.
This doubling of the two characters' identities (the fissure between their "true" self and their performance) is brilliantly highlighted in the editing of some of the sex scenes. There's a visual doubling the occurs with two copies of the same image layered on top of each other (as if the camera had its eyes crossed). This is the moment when the two halves, identity and performance, can finally coexist within the same frame. They are both enjoying each other as themselves and as their performances. The two halves of each partner don't unite into one (hence the visual doubling), the point is rather that they can exist together simultaneously. They are joined without the impossible fantasy of finally being made into a singular, cohesive whole.
From here we start to see how this performance can be a struggle for both parties. Cythia feels Evelyn falling more for the fetishized performance than for her real self, and Evelyn feels the performance unsatisfactory as Cynthia falters in maintaining it. The gap between the two lovers begins to grow at the same time that the gap between the lovers and their romantic performances grows. They argue about each other's willingness to participate in their respective fantasies, but it's presented with a sublime, honest sympathy for that struggle and for the necessity of fantasy (see this scene from The Break-Up for a perfect example of how to illustrate this same idea without that sympathy).
These are the fluctuations felt across any romantic relationship; this is the film's access point between the specificity of sadomasochism and the universality of true love. Perversion portrayed not as radical otherness, but as mundane normalcy, as the tenderness and intimacy and the anger and frustration inherent to any desire. This is one of the many things The Duke of Burgundy really nails. The point is that love doesn't mean finding the one person you're made to be with, it's about maintaining a certain performance. Love is work, here both figuratively and literally—not in a pessimistic way, but in a way that shows how beautiful and fulfilling and truly romantic working for (and possibly submitting to) your romantic partner can be.