I am in a BDSM relationship. It is my first and I've had long term vanilla relationships in the past. I have never suffered abuse, I am not being abused, I have driven the experimentation and we talk long and hard before trying new things. He struggled at first with worries that he was controlling or abusing me. He is not.
We don't do choking, it doesn't appeal to me and it is too risky for me to want to test drive when I don't feel strongly about it.
I don't believe that vanilla sex is wrong or that BDSM is or should be the "norm". In the same way some people don't enjoy giving head and shouldn't be expected to do so, I accept that most people don't enjoy being spanked and shouldn't be expected to do so.
For those asking why anyone would want to be in a relationship like this it is the same answer as to why anyone would want to have sex when not actively trying to conceive. It feels good. I enjoy the sensations, it is something I find sexually exciting. If my partner didn't want to at least try then we'd be a vanilla couple and that would be ok. He was willing to test the waters and he enjoys my obvious enjoyment. I can't imagine he'd take this and apply it from day 1 to any new partner. That would be scary and abusive!