Anna brings Stephen CLOSER to Martyn

They have a conversation at one point in the film about how there was a lack of passion or warmth in Martyn's childhood. Only through his relationship with Anna does Stephen finally find a way to communicate with his son and understand his son's disappointment about this, which validates Martyn on a profound level. Stephen is finally able to speak Martyn's language and had it not been for Anna, he would have remained closed off and remote. It's just about the way you look at things. The sex was really about how Stephen was able to evolve as a human being and become more spontaneous and instinctual. Anna brought Stephen into a primal consciousness so by the end of the film, he truly wants a relationship with his son. This film is so multi layered like that. There is a truly positive narrative arc about personal growth which is aligned to the negative one (the destruction of families and traditional ways of thinking/preserving what one has built).