Do you have to have sex to have a BDSM relationship? Is sex love? Does love necessarily require sex? A lot depends on your definition of 'Love' and this is one of the most nebulous things to define in the history of definitions.

BDSM sessions can be intense and intimate without involving much in the way of sexual contact and therefore border on what you may call love. BDSM requires a lot of trust as well as intimacy and both are commonly regarded as being essential for a loving relationship.

I would say that it is more likely that a deep, loving relationship would develop between a BDSM couple than a vanilla couple because that trust has to be there for the relationship to even start. Its not essential for it to exist (in the same way as it is not, in truth, essential to love someone to sleep with them you just have to have the lust) but it is more likely to develop.