Working through those post-scene blues, not really sure where they've come from. Interesting to note that the last time I was very down it felt different, lonesome. I don't feel especially lonely, just sad. Reading up on the changes in the body during sex, after orgasm and also the wash of hormones evoked by a power exchange or similar stressful situation.Yes, I suppose it could be put down to biology, but whilst I like to contextualise and think things through I believe that there is a danger in rationalising the emotional. Smashing a square peg into a round hole and then wondering why it doesn't quite fit.
I found an article by Sudhir Kakar, who has some noteworthy ideas on sex and spirituality which seemed to well express some of the sensations I've experienced in BDSM. He talks about good sex as being transcendent of being capable of taking you out of the here and now and giving more than orgasm. I normally dislike linking any form of religious sentiment to physical satisfaction - it feels like over-glorification at best and slightly blasphemous at worst.
However there is value in the idea because there are aspects of kink that I particularly enjoy and get the most out of that go beyond the physical and are not rational. Those peculiar head-spaces where one can be both lost and found, blissfully contradictory. I certainly don't mean to imply that all forms of fucking must necessarily strive to become "spiritual" most things are what they are and none the worse for it. But some experiences are more powerful than others and they do provide something a little deeper than just a pleasurable skin-to-skin or even brain-to-brain connection.
So, in the absence of that, afterwards, perhaps one can justifiably feel a little sorrow.