I would love to agree with Kore in whole on this, but that's really the hopeless romantic in me speaking and wouldn't be the truth.

Not everyone who decides to go into a bdsm relationship necessarily wants to be in love with their partner(s).

There is such a thing as "casual" play partners, (especially in the fet-ball circuit (not to mention many public access dungeons and clubs) sometimes so casual as to be in the realm of one night stands or public exhibitions with multiple "casual" partners plural joining in or observing and when one is in such usually monitored situations (at least in the case of most clubs etc) and its in a more private setting...things can get outside comfort zones quickly.

Sometimes one or both or more parties can even have been previously comfortable doing a given thing with person A.), and then turn right around and be uncomfortable with the same person in a different session (or even during) or uncomfortable doing said thing with anyone else, or just becuase person X.) is present etc.