A man with two women had better watch his back. That's all I have to say about that.
Okay, sex beyond desire, if you must. What's that like? I can't imagine that it could contain role playing, so...pretty much everything kinky is out. No spanking, obviously. No dress up games. Maybe cuddling, and stroking, and raising your kundalini or something chakra-y, but no naughty stuff.
Maybe it's all about power. Sex, in a cultural sense, seems to be about establishing, and ceremonially reinforcing a social pogrom of domination and submission roles. Take away the will to power and the need to procreate. What kind of sex happens without those two things?