If we think of Almodóvar’s The Skin I Live In or the selkie myth as captivity narratives and maintain the dichotomy of captor/captive, then we could say that the female skin is the compliant false mask that allows her to maintain the integral part of herself intact when her freedom is taken from her. Yet captivity narratives are often unsettlingly ambiguous. What of Stockholm Syndrome, famously personified by Patty Hearst, who joined the liberation army that kidnapped her? Or such fictional portrayals as Liliana Cavani’s 1974 The Night Porter, in which the concentration camp survivor and her former SS imprisoner continue their sadomasochistic relationship 13 years after the war, choosing to die together in a trap of their own making.
Or Jorge Luis Borges’ story “The Warrior and the Captive,” in which the white woman in the 1870s Argentine frontier is taken captive by an indigenous tribe and forced to be the chief’s wife, only to refuse rescue many years later, choosing instead to stay with the tribe. These are stories that show the imbrication between the pursuer and the pursued, the ways in which desire unsettles individual certainties and boundaries. It even becomes hard to separate out who is passive or active, caged or free. As the Beatles say, “I once had a girl. Or should I say, she once had me.”
When The Skin I Live In’s Vicente escapes to return to his home, he does not return the same as when he was taken away from it. The process of splitting and inhabiting his imposed skin has inevitably led him into other identities and realities. There is no untouchable person that remains intact underneath the skin, and, at the same time, no container that can fully define all the contradictions and planes that make up a surface. Different angles afford different realities, perceptions.
Perhaps the fantasy of interiority, of a true self contained within skin, is a male one that produces a frustration in which that truth remains always elusive and secret. Dr. Ledgard or the selkie’s husband is obsessive in his deluded and disturbed desire to gain control over that unknown quality. Unable to bear the discomfort of having to remain in a space of uncertainty in which the loved one could not love back, could run away, could get hurt, could die, he entraps her in a life that forces her to feel split, at odds with her exterior constraints. If he can keep her captive he can have her, he can build an imagined life with her. Think, most horribly, of Austrian Josef Fritzl, who imprisoned his daughter in his cellar for 24 years, saying that he knew she would start doing drugs and having sex if he didn’t. But to keep her captive still doesn’t mean he knows her. He can look at her, stroke, taste, smell, and fuck her, but she will always exceed him, her skin both as site of proximity and of insurmountable distance. Frustration and fear emerge when he is faced with the immensity of her unknowability which cannot be contained. This has a particularly acute valence in the case of the incestuous captivity trauma. Fritzl’s daughter is his own “flesh and blood”, and so in imprisoning her he is futiley trying to contain what is both part of himself and irrevocably separate from him. 
What is it that the man imagines about the disconnect between appearance and interiority? That beauty is more than skin deep, that though she may present as one thing, inside she is something else? Why would he think this of her? Because, perhaps, he’s projecting onto her his own idea of himself. As Zizek has said,
Man wants to be loved for what he truly is; which is why the archetypal male scenario of the trial of woman’s love is that of the prince from a fairy tale who first approaches his beloved under the guise of a poor servant, in order to insure that the woman will fall in love with him for himself, not for his princely title. This, however, is precisely what a woman doesn’t want—and is this not yet another confirmation of the fact that woman is more subject than man? A man stupidly believes that, beyond his symbolic title, there is deep in himself some substantial content, some hidden treasure which makes him worthy of love, whereas a woman knows that there is nothing beneath the mask—her strategy is precisely to preserve this ‘nothing’ of her freedom, out of reach of man’s possessive love….
If man believes himself to be more than skin deep, than he must perceive woman as hiding something, rendering herself deliberately opaque in a way that demands penetration, that wants to “get inside.” If she can only be encased, enveloped, contained, caged, then “she” and the ramifications of her meanings can be perhaps discerned. And if she has interiority, if her body is a full vessel, than it verifies that he too is whole.
 Thanks to Jaye Fischel for pointing this out.